class Sequel::Dataset
A dataset represents an SQL
query. Datasets can be used to select, insert, update and delete records.
Query
results are always retrieved on demand, so a dataset can be kept around and reused indefinitely (datasets never cache results):
my_posts = DB[:posts].where(author: 'david') # no records are retrieved my_posts.all # records are retrieved my_posts.all # records are retrieved again
Datasets are frozen and use a functional style where modification methods return modified copies of the the dataset. This allows you to reuse datasets:
posts = DB[:posts] davids_posts = posts.where(author: 'david') old_posts = posts.where{stamp < Date.today - 7} davids_old_posts = davids_posts.where{stamp < Date.today - 7}
Datasets are Enumerable objects, so they can be manipulated using many of the Enumerable methods, such as map
and inject
. Note that there are some methods that Dataset
defines that override methods defined in Enumerable and result in different behavior, such as select
and group_by
.
For more information, see the “Dataset Basics” guide.
Constants
- OPTS
- TRUE_FREEZE
Whether
Dataset#freeze
can actually freeze datasets. True only on ruby 2.4+, as it requires clone(freeze: false)
1 - Methods that return modified datasets
↑ topConstants
- COLUMN_CHANGE_OPTS
The dataset options that require the removal of cached columns if changed.
- CONDITIONED_JOIN_TYPES
These symbols have _join methods created (e.g. inner_join) that call
join_table
with the symbol, passing along the arguments and block from the method call.- EMPTY_ARRAY
- EXTENSIONS
Hash
of extension name symbols to callable objects to load the extension into theDataset
object (usually by extending it with a module defined in the extension).- JOIN_METHODS
All methods that return modified datasets with a joined table added.
- NON_SQL_OPTIONS
Which options don’t affect the
SQL
generation. Used by simple_select_all? to determine if this is a simple SELECT * FROM table.- QUERY_METHODS
Methods that return modified datasets
- SIMPLE_SELECT_ALL_ALLOWED_FROM
From types allowed to be considered a simple_select_all
- UNCONDITIONED_JOIN_TYPES
These symbols have _join methods created (e.g. natural_join). They accept a table argument and options hash which is passed to
join_table
, and they raise an error if called with a block.
Public Class Methods
Register an extension callback for Dataset
objects. ext should be the extension name symbol, and mod should either be a Module that the dataset is extended with, or a callable object called with the database object. If mod is not provided, a block can be provided and is treated as the mod object.
If mod is a module, this also registers a Database
extension that will extend all of the database’s datasets.
# File lib/sequel/dataset/query.rb 55 def self.register_extension(ext, mod=nil, &block) 56 if mod 57 raise(Error, "cannot provide both mod and block to Dataset.register_extension") if block 58 if mod.is_a?(Module) 59 block = proc{|ds| ds.extend(mod)} 60 Sequel::Database.register_extension(ext){|db| db.extend_datasets(mod)} 61 else 62 block = mod 63 end 64 end 65 Sequel.synchronize{EXTENSIONS[ext] = block} 66 end
Public Instance Methods
Save original clone implementation, as some other methods need to call it internally.
Returns a new clone of the dataset with the given options merged. If the options changed include options in COLUMN_CHANGE_OPTS
, the cached columns are deleted. This method should generally not be called directly by user code.
# File lib/sequel/dataset/query.rb 84 def clone(opts = nil || (return self)) 85 # return self used above because clone is called by almost all 86 # other query methods, and it is the fastest approach 87 c = super(:freeze=>false) 88 c.opts.merge!(opts) 89 unless opts.each_key{|o| break if COLUMN_CHANGE_OPTS.include?(o)} 90 c.clear_columns_cache 91 end 92 c.freeze 93 end
Returns a copy of the dataset with the SQL
DISTINCT clause. The DISTINCT clause is used to remove duplicate rows from the output. If arguments are provided, uses a DISTINCT ON clause, in which case it will only be distinct on those columns, instead of all returned columns. If a block is given, it is treated as a virtual row block, similar to where
. Raises an error if arguments are given and DISTINCT ON is not supported.
DB[:items].distinct # SQL: SELECT DISTINCT * FROM items DB[:items].order(:id).distinct(:id) # SQL: SELECT DISTINCT ON (id) * FROM items ORDER BY id DB[:items].order(:id).distinct{func(:id)} # SQL: SELECT DISTINCT ON (func(id)) * FROM items ORDER BY id
There is support for emualting the DISTINCT ON support in MySQL
, but it does not support the ORDER of the dataset, and also doesn’t work in many cases if the ONLY_FULL_GROUP_BY sql_mode is used, which is the default on MySQL
5.7.5+.
# File lib/sequel/dataset/query.rb 123 def distinct(*args, &block) 124 virtual_row_columns(args, block) 125 if args.empty? 126 cached_dataset(:_distinct_ds){clone(:distinct => EMPTY_ARRAY)} 127 else 128 raise(InvalidOperation, "DISTINCT ON not supported") unless supports_distinct_on? 129 clone(:distinct => args.freeze) 130 end 131 end
Adds an EXCEPT clause using a second dataset object. An EXCEPT compound dataset returns all rows in the current dataset that are not in the given dataset. Raises an InvalidOperation
if the operation is not supported. Options:
- :alias
-
Use the given value as the
from_self
alias - :all
-
Set to true to use EXCEPT ALL instead of EXCEPT, so duplicate rows can occur
- :from_self
-
Set to false to not wrap the returned dataset in a
from_self
, use with care.
DB[:items].except(DB[:other_items]) # SELECT * FROM (SELECT * FROM items EXCEPT SELECT * FROM other_items) AS t1 DB[:items].except(DB[:other_items], all: true, from_self: false) # SELECT * FROM items EXCEPT ALL SELECT * FROM other_items DB[:items].except(DB[:other_items], alias: :i) # SELECT * FROM (SELECT * FROM items EXCEPT SELECT * FROM other_items) AS i
# File lib/sequel/dataset/query.rb 150 def except(dataset, opts=OPTS) 151 raise(InvalidOperation, "EXCEPT not supported") unless supports_intersect_except? 152 raise(InvalidOperation, "EXCEPT ALL not supported") if opts[:all] && !supports_intersect_except_all? 153 compound_clone(:except, dataset, opts) 154 end
Performs the inverse of Dataset#where
. Note that if you have multiple filter conditions, this is not the same as a negation of all conditions.
DB[:items].exclude(category: 'software') # SELECT * FROM items WHERE (category != 'software') DB[:items].exclude(category: 'software', id: 3) # SELECT * FROM items WHERE ((category != 'software') OR (id != 3))
Also note that SQL
uses 3-valued boolean logic (true
, false
, NULL
), so the inverse of a true condition is a false condition, and will still not match rows that were NULL originally. If you take the earlier example:
DB[:items].exclude(category: 'software') # SELECT * FROM items WHERE (category != 'software')
Note that this does not match rows where category
is NULL
. This is because NULL
is an unknown value, and you do not know whether or not the NULL
category is software
. You can explicitly specify how to handle NULL
values if you want:
DB[:items].exclude(Sequel.~(category: nil) & {category: 'software'}) # SELECT * FROM items WHERE ((category IS NULL) OR (category != 'software'))
# File lib/sequel/dataset/query.rb 180 def exclude(*cond, &block) 181 add_filter(:where, cond, true, &block) 182 end
Inverts the given conditions and adds them to the HAVING clause.
DB[:items].select_group(:name).exclude_having{count(name) < 2} # SELECT name FROM items GROUP BY name HAVING (count(name) >= 2)
See documentation for exclude for how inversion is handled in regards to SQL
3-valued boolean logic.
# File lib/sequel/dataset/query.rb 191 def exclude_having(*cond, &block) 192 add_filter(:having, cond, true, &block) 193 end
Return a clone of the dataset loaded with the given dataset extensions. If no related extension file exists or the extension does not have specific support for Dataset
objects, an Error
will be raised.
# File lib/sequel/dataset/query.rb 199 def extension(*a) 200 c = _clone(:freeze=>false) 201 c.send(:_extension!, a) 202 c.freeze 203 end
Alias for where.
# File lib/sequel/dataset/query.rb 215 def filter(*cond, &block) 216 where(*cond, &block) 217 end
Returns a cloned dataset with a :update lock style.
DB[:table].for_update # SELECT * FROM table FOR UPDATE
# File lib/sequel/dataset/query.rb 222 def for_update 223 cached_dataset(:_for_update_ds){lock_style(:update)} 224 end
Returns a copy of the dataset with the source changed. If no source is given, removes all tables. If multiple sources are given, it is the same as using a CROSS JOIN (cartesian product) between all tables. If a block is given, it is treated as a virtual row block, similar to where
.
DB[:items].from # SQL: SELECT * DB[:items].from(:blah) # SQL: SELECT * FROM blah DB[:items].from(:blah, :foo) # SQL: SELECT * FROM blah, foo DB[:items].from{fun(arg)} # SQL: SELECT * FROM fun(arg)
# File lib/sequel/dataset/query.rb 235 def from(*source, &block) 236 virtual_row_columns(source, block) 237 table_alias_num = 0 238 ctes = nil 239 source.map! do |s| 240 case s 241 when Dataset 242 if hoist_cte?(s) 243 ctes ||= [] 244 ctes += s.opts[:with] 245 s = s.clone(:with=>nil) 246 end 247 SQL::AliasedExpression.new(s, dataset_alias(table_alias_num+=1)) 248 when Symbol 249 sch, table, aliaz = split_symbol(s) 250 if aliaz 251 s = sch ? SQL::QualifiedIdentifier.new(sch, table) : SQL::Identifier.new(table) 252 SQL::AliasedExpression.new(s, aliaz.to_sym) 253 else 254 s 255 end 256 else 257 s 258 end 259 end 260 o = {:from=>source.empty? ? nil : source.freeze} 261 o[:with] = ((opts[:with] || EMPTY_ARRAY) + ctes).freeze if ctes 262 o[:num_dataset_sources] = table_alias_num if table_alias_num > 0 263 clone(o) 264 end
Returns a dataset selecting from the current dataset. Options:
- :alias
-
Controls the alias of the table
- :column_aliases
-
Also aliases columns, using derived column lists. Only used in conjunction with :alias.
ds = DB[:items].order(:name).select(:id, :name) # SELECT id,name FROM items ORDER BY name ds.from_self # SELECT * FROM (SELECT id, name FROM items ORDER BY name) AS t1 ds.from_self(alias: :foo) # SELECT * FROM (SELECT id, name FROM items ORDER BY name) AS foo ds.from_self(alias: :foo, column_aliases: [:c1, :c2]) # SELECT * FROM (SELECT id, name FROM items ORDER BY name) AS foo(c1, c2)
# File lib/sequel/dataset/query.rb 283 def from_self(opts=OPTS) 284 fs = {} 285 @opts.keys.each{|k| fs[k] = nil unless non_sql_option?(k)} 286 pr = proc do 287 c = clone(fs).from(opts[:alias] ? as(opts[:alias], opts[:column_aliases]) : self) 288 if cols = _columns 289 c.send(:columns=, cols) 290 end 291 c 292 end 293 294 opts.empty? ? cached_dataset(:_from_self_ds, &pr) : pr.call 295 end
Match any of the columns to any of the patterns. The terms can be strings (which use LIKE) or regular expressions if the database supports that. Note that the total number of pattern matches will be Array(columns).length * Array(terms).length, which could cause performance issues.
Options (all are boolean):
- :all_columns
-
All columns must be matched to any of the given patterns.
- :all_patterns
-
All patterns must match at least one of the columns.
- :case_insensitive
-
Use a case insensitive pattern match (the default is case sensitive if the database supports it).
If both :all_columns and :all_patterns are true, all columns must match all patterns.
Examples:
dataset.grep(:a, '%test%') # SELECT * FROM items WHERE (a LIKE '%test%' ESCAPE '\') dataset.grep([:a, :b], %w'%test% foo') # SELECT * FROM items WHERE ((a LIKE '%test%' ESCAPE '\') OR (a LIKE 'foo' ESCAPE '\') # OR (b LIKE '%test%' ESCAPE '\') OR (b LIKE 'foo' ESCAPE '\')) dataset.grep([:a, :b], %w'%foo% %bar%', all_patterns: true) # SELECT * FROM a WHERE (((a LIKE '%foo%' ESCAPE '\') OR (b LIKE '%foo%' ESCAPE '\')) # AND ((a LIKE '%bar%' ESCAPE '\') OR (b LIKE '%bar%' ESCAPE '\'))) dataset.grep([:a, :b], %w'%foo% %bar%', all_columns: true) # SELECT * FROM a WHERE (((a LIKE '%foo%' ESCAPE '\') OR (a LIKE '%bar%' ESCAPE '\')) # AND ((b LIKE '%foo%' ESCAPE '\') OR (b LIKE '%bar%' ESCAPE '\'))) dataset.grep([:a, :b], %w'%foo% %bar%', all_patterns: true, all_columns: true) # SELECT * FROM a WHERE ((a LIKE '%foo%' ESCAPE '\') AND (b LIKE '%foo%' ESCAPE '\') # AND (a LIKE '%bar%' ESCAPE '\') AND (b LIKE '%bar%' ESCAPE '\'))
# File lib/sequel/dataset/query.rb 332 def grep(columns, patterns, opts=OPTS) 333 column_op = opts[:all_columns] ? :AND : :OR 334 if opts[:all_patterns] 335 conds = Array(patterns).map do |pat| 336 SQL::BooleanExpression.new(column_op, *Array(columns).map{|c| SQL::StringExpression.like(c, pat, opts)}) 337 end 338 where(SQL::BooleanExpression.new(:AND, *conds)) 339 else 340 conds = Array(columns).map do |c| 341 SQL::BooleanExpression.new(:OR, *Array(patterns).map{|pat| SQL::StringExpression.like(c, pat, opts)}) 342 end 343 where(SQL::BooleanExpression.new(column_op, *conds)) 344 end 345 end
Returns a copy of the dataset with the results grouped by the value of the given columns. If a block is given, it is treated as a virtual row block, similar to where
.
DB[:items].group(:id) # SELECT * FROM items GROUP BY id DB[:items].group(:id, :name) # SELECT * FROM items GROUP BY id, name DB[:items].group{[a, sum(b)]} # SELECT * FROM items GROUP BY a, sum(b)
# File lib/sequel/dataset/query.rb 354 def group(*columns, &block) 355 virtual_row_columns(columns, block) 356 clone(:group => (columns.compact.empty? ? nil : columns.freeze)) 357 end
Returns a dataset grouped by the given column with count by group. Column aliases may be supplied, and will be included in the select clause. If a block is given, it is treated as a virtual row block, similar to where
.
Examples:
DB[:items].group_and_count(:name).all # SELECT name, count(*) AS count FROM items GROUP BY name # => [{:name=>'a', :count=>1}, ...] DB[:items].group_and_count(:first_name, :last_name).all # SELECT first_name, last_name, count(*) AS count FROM items GROUP BY first_name, last_name # => [{:first_name=>'a', :last_name=>'b', :count=>1}, ...] DB[:items].group_and_count(Sequel[:first_name].as(:name)).all # SELECT first_name AS name, count(*) AS count FROM items GROUP BY first_name # => [{:name=>'a', :count=>1}, ...] DB[:items].group_and_count{substr(:first_name, 1, 1).as(:initial)}.all # SELECT substr(first_name, 1, 1) AS initial, count(*) AS count FROM items GROUP BY substr(first_name, 1, 1) # => [{:initial=>'a', :count=>1}, ...]
# File lib/sequel/dataset/query.rb 385 def group_and_count(*columns, &block) 386 select_group(*columns, &block).select_append(COUNT_OF_ALL_AS_COUNT) 387 end
Returns a copy of the dataset with the given columns added to the list of existing columns to group on. If no existing columns are present this method simply sets the columns as the initial ones to group on.
DB[:items].group_append(:b) # SELECT * FROM items GROUP BY b DB[:items].group(:a).group_append(:b) # SELECT * FROM items GROUP BY a, b
# File lib/sequel/dataset/query.rb 395 def group_append(*columns, &block) 396 columns = @opts[:group] + columns if @opts[:group] 397 group(*columns, &block) 398 end
Alias of group
# File lib/sequel/dataset/query.rb 360 def group_by(*columns, &block) 361 group(*columns, &block) 362 end
Adds the appropriate CUBE syntax to GROUP BY.
# File lib/sequel/dataset/query.rb 401 def group_cube 402 raise Error, "GROUP BY CUBE not supported on #{db.database_type}" unless supports_group_cube? 403 clone(:group_options=>:cube) 404 end
Adds the appropriate ROLLUP syntax to GROUP BY.
# File lib/sequel/dataset/query.rb 407 def group_rollup 408 raise Error, "GROUP BY ROLLUP not supported on #{db.database_type}" unless supports_group_rollup? 409 clone(:group_options=>:rollup) 410 end
Adds the appropriate GROUPING SETS syntax to GROUP BY.
# File lib/sequel/dataset/query.rb 413 def grouping_sets 414 raise Error, "GROUP BY GROUPING SETS not supported on #{db.database_type}" unless supports_grouping_sets? 415 clone(:group_options=>:"grouping sets") 416 end
Returns a copy of the dataset with the HAVING conditions changed. See where
for argument types.
DB[:items].group(:sum).having(sum: 10) # SELECT * FROM items GROUP BY sum HAVING (sum = 10)
# File lib/sequel/dataset/query.rb 422 def having(*cond, &block) 423 add_filter(:having, cond, &block) 424 end
Adds an INTERSECT clause using a second dataset object. An INTERSECT compound dataset returns all rows in both the current dataset and the given dataset. Raises an InvalidOperation
if the operation is not supported. Options:
- :alias
-
Use the given value as the
from_self
alias - :all
-
Set to true to use INTERSECT ALL instead of INTERSECT, so duplicate rows can occur
- :from_self
-
Set to false to not wrap the returned dataset in a
from_self
, use with care.
DB[:items].intersect(DB[:other_items]) # SELECT * FROM (SELECT * FROM items INTERSECT SELECT * FROM other_items) AS t1 DB[:items].intersect(DB[:other_items], all: true, from_self: false) # SELECT * FROM items INTERSECT ALL SELECT * FROM other_items DB[:items].intersect(DB[:other_items], alias: :i) # SELECT * FROM (SELECT * FROM items INTERSECT SELECT * FROM other_items) AS i
# File lib/sequel/dataset/query.rb 443 def intersect(dataset, opts=OPTS) 444 raise(InvalidOperation, "INTERSECT not supported") unless supports_intersect_except? 445 raise(InvalidOperation, "INTERSECT ALL not supported") if opts[:all] && !supports_intersect_except_all? 446 compound_clone(:intersect, dataset, opts) 447 end
Inverts the current WHERE and HAVING clauses. If there is neither a WHERE or HAVING clause, adds a WHERE clause that is always false.
DB[:items].where(category: 'software').invert # SELECT * FROM items WHERE (category != 'software') DB[:items].where(category: 'software', id: 3).invert # SELECT * FROM items WHERE ((category != 'software') OR (id != 3))
See documentation for exclude for how inversion is handled in regards to SQL
3-valued boolean logic.
# File lib/sequel/dataset/query.rb 460 def invert 461 cached_dataset(:_invert_ds) do 462 having, where = @opts.values_at(:having, :where) 463 if having.nil? && where.nil? 464 where(false) 465 else 466 o = {} 467 o[:having] = SQL::BooleanExpression.invert(having) if having 468 o[:where] = SQL::BooleanExpression.invert(where) if where 469 clone(o) 470 end 471 end 472 end
Alias of inner_join
# File lib/sequel/dataset/query.rb 475 def join(*args, &block) 476 inner_join(*args, &block) 477 end
Returns a joined dataset. Not usually called directly, users should use the appropriate join method (e.g. join, left_join, natural_join, cross_join) which fills in the type
argument.
Takes the following arguments:
- type
-
The type of join to do (e.g. :inner)
- table
-
table to join into the current dataset. Generally one of the following types:
String
,Symbol
-
identifier used as table or view name
Dataset
-
a subselect is performed with an alias of tN for some value of N
SQL::Function
-
set returning function
SQL::AliasedExpression
-
already aliased expression. Uses given alias unless overridden by the :table_alias option.
- expr
-
conditions used when joining, depends on type:
Hash
,Array
of pairs-
Assumes key (1st arg) is column of joined table (unless already qualified), and value (2nd arg) is column of the last joined or primary table (or the :implicit_qualifier option). To specify multiple conditions on a single joined table column, you must use an array. Uses a JOIN with an ON clause.
Array
-
If all members of the array are symbols, considers them as columns and uses a JOIN with a USING clause. Most databases will remove duplicate columns from the result set if this is used.
- nil
-
If a block is not given, doesn’t use ON or USING, so the JOIN should be a NATURAL or CROSS join. If a block is given, uses an ON clause based on the block, see below.
- otherwise
-
Treats the argument as a filter expression, so strings are considered literal, symbols specify boolean columns, and
Sequel
expressions can be used. Uses a JOIN with an ON clause.
- options
-
a hash of options, with the following keys supported:
- :table_alias
-
Override the table alias used when joining. In general you shouldn’t use this option, you should provide the appropriate
SQL::AliasedExpression
as the table argument. - :implicit_qualifier
-
The name to use for qualifying implicit conditions. By default, the last joined or primary table is used.
- :join_using
-
Force the using of JOIN USING, even if
expr
is not an array of symbols. - :reset_implicit_qualifier
-
Can set to false to ignore this join when future joins determine qualifier for implicit conditions.
- :qualify
-
Can be set to false to not do any implicit qualification. Can be set to :deep to use the
Qualifier
AST Transformer, which will attempt to qualify subexpressions of the expression tree. Can be set to :symbol to only qualify symbols. Defaults to the value of default_join_table_qualification.
- block
-
The block argument should only be given if a JOIN with an ON clause is used, in which case it yields the table alias/name for the table currently being joined, the table alias/name for the last joined (or first table), and an array of previous
SQL::JoinClause
. Unlikewhere
, this block is not treated as a virtual row block.
Examples:
DB[:a].join_table(:cross, :b) # SELECT * FROM a CROSS JOIN b DB[:a].join_table(:inner, DB[:b], c: d) # SELECT * FROM a INNER JOIN (SELECT * FROM b) AS t1 ON (t1.c = a.d) DB[:a].join_table(:left, Sequel[:b].as(:c), [:d]) # SELECT * FROM a LEFT JOIN b AS c USING (d) DB[:a].natural_join(:b).join_table(:inner, :c) do |ta, jta, js| (Sequel.qualify(ta, :d) > Sequel.qualify(jta, :e)) & {Sequel.qualify(ta, :f)=>DB.from(js.first.table).select(:g)} end # SELECT * FROM a NATURAL JOIN b INNER JOIN c # ON ((c.d > b.e) AND (c.f IN (SELECT g FROM b)))
# File lib/sequel/dataset/query.rb 539 def join_table(type, table, expr=nil, options=OPTS, &block) 540 if hoist_cte?(table) 541 s, ds = hoist_cte(table) 542 return s.join_table(type, ds, expr, options, &block) 543 end 544 545 using_join = options[:join_using] || (expr.is_a?(Array) && !expr.empty? && expr.all?{|x| x.is_a?(Symbol)}) 546 if using_join && !supports_join_using? 547 h = {} 548 expr.each{|e| h[e] = e} 549 return join_table(type, table, h, options) 550 end 551 552 table_alias = options[:table_alias] 553 554 if table.is_a?(SQL::AliasedExpression) 555 table_expr = if table_alias 556 SQL::AliasedExpression.new(table.expression, table_alias, table.columns) 557 else 558 table 559 end 560 table = table_expr.expression 561 table_name = table_alias = table_expr.alias 562 elsif table.is_a?(Dataset) 563 if table_alias.nil? 564 table_alias_num = (@opts[:num_dataset_sources] || 0) + 1 565 table_alias = dataset_alias(table_alias_num) 566 end 567 table_name = table_alias 568 table_expr = SQL::AliasedExpression.new(table, table_alias) 569 else 570 table, implicit_table_alias = split_alias(table) 571 table_alias ||= implicit_table_alias 572 table_name = table_alias || table 573 table_expr = table_alias ? SQL::AliasedExpression.new(table, table_alias) : table 574 end 575 576 join = if expr.nil? and !block 577 SQL::JoinClause.new(type, table_expr) 578 elsif using_join 579 raise(Sequel::Error, "can't use a block if providing an array of symbols as expr") if block 580 SQL::JoinUsingClause.new(expr, type, table_expr) 581 else 582 last_alias = options[:implicit_qualifier] || @opts[:last_joined_table] || first_source_alias 583 qualify_type = options[:qualify] 584 if Sequel.condition_specifier?(expr) 585 expr = expr.map do |k, v| 586 qualify_type = default_join_table_qualification if qualify_type.nil? 587 case qualify_type 588 when false 589 nil # Do no qualification 590 when :deep 591 k = Sequel::Qualifier.new(table_name).transform(k) 592 v = Sequel::Qualifier.new(last_alias).transform(v) 593 else 594 k = qualified_column_name(k, table_name) if k.is_a?(Symbol) 595 v = qualified_column_name(v, last_alias) if v.is_a?(Symbol) 596 end 597 [k,v] 598 end 599 expr = SQL::BooleanExpression.from_value_pairs(expr) 600 end 601 if block 602 expr2 = yield(table_name, last_alias, @opts[:join] || EMPTY_ARRAY) 603 expr = expr ? SQL::BooleanExpression.new(:AND, expr, expr2) : expr2 604 end 605 SQL::JoinOnClause.new(expr, type, table_expr) 606 end 607 608 opts = {:join => ((@opts[:join] || EMPTY_ARRAY) + [join]).freeze} 609 opts[:last_joined_table] = table_name unless options[:reset_implicit_qualifier] == false 610 opts[:num_dataset_sources] = table_alias_num if table_alias_num 611 clone(opts) 612 end
Marks this dataset as a lateral dataset. If used in another dataset’s FROM or JOIN clauses, it will surround the subquery with LATERAL to enable it to deal with previous tables in the query:
DB.from(:a, DB[:b].where(Sequel[:a][:c]=>Sequel[:b][:d]).lateral) # SELECT * FROM a, LATERAL (SELECT * FROM b WHERE (a.c = b.d))
# File lib/sequel/dataset/query.rb 633 def lateral 634 cached_dataset(:_lateral_ds){clone(:lateral=>true)} 635 end
If given an integer, the dataset will contain only the first l results. If given a range, it will contain only those at offsets within that range. If a second argument is given, it is used as an offset. To use an offset without a limit, pass nil as the first argument.
DB[:items].limit(10) # SELECT * FROM items LIMIT 10 DB[:items].limit(10, 20) # SELECT * FROM items LIMIT 10 OFFSET 20 DB[:items].limit(10...20) # SELECT * FROM items LIMIT 10 OFFSET 10 DB[:items].limit(10..20) # SELECT * FROM items LIMIT 11 OFFSET 10 DB[:items].limit(nil, 20) # SELECT * FROM items OFFSET 20
# File lib/sequel/dataset/query.rb 647 def limit(l, o = (no_offset = true; nil)) 648 return from_self.limit(l, o) if @opts[:sql] 649 650 if l.is_a?(Range) 651 no_offset = false 652 o = l.first 653 l = l.last - l.first + (l.exclude_end? ? 0 : 1) 654 end 655 l = l.to_i if l.is_a?(String) && !l.is_a?(LiteralString) 656 if l.is_a?(Integer) 657 raise(Error, 'Limits must be greater than or equal to 1') unless l >= 1 658 end 659 660 ds = clone(:limit=>l) 661 ds = ds.offset(o) unless no_offset 662 ds 663 end
Returns a cloned dataset with the given lock style. If style is a string, it will be used directly. You should never pass a string to this method that is derived from user input, as that can lead to SQL
injection.
A symbol may be used for database independent locking behavior, but all supported symbols have separate methods (e.g. for_update
).
DB[:items].lock_style('FOR SHARE NOWAIT') # SELECT * FROM items FOR SHARE NOWAIT DB[:items].lock_style('FOR UPDATE OF table1 SKIP LOCKED') # SELECT * FROM items FOR UPDATE OF table1 SKIP LOCKED
# File lib/sequel/dataset/query.rb 677 def lock_style(style) 678 clone(:lock => style) 679 end
Returns a cloned dataset without a row_proc.
ds = DB[:items].with_row_proc(:invert.to_proc) ds.all # => [{2=>:id}] ds.naked.all # => [{:id=>2}]
# File lib/sequel/dataset/query.rb 686 def naked 687 cached_dataset(:_naked_ds){with_row_proc(nil)} 688 end
Returns a copy of the dataset that will raise a DatabaseLockTimeout instead of waiting for rows that are locked by another transaction
DB[:items].for_update.nowait # SELECT * FROM items FOR UPDATE NOWAIT
# File lib/sequel/dataset/query.rb 695 def nowait 696 cached_dataset(:_nowait_ds) do 697 raise(Error, 'This dataset does not support raises errors instead of waiting for locked rows') unless supports_nowait? 698 clone(:nowait=>true) 699 end 700 end
Returns a copy of the dataset with a specified order. Can be safely combined with limit. If you call limit with an offset, it will override the offset if you’ve called offset first.
DB[:items].offset(10) # SELECT * FROM items OFFSET 10
# File lib/sequel/dataset/query.rb 707 def offset(o) 708 o = o.to_i if o.is_a?(String) && !o.is_a?(LiteralString) 709 if o.is_a?(Integer) 710 raise(Error, 'Offsets must be greater than or equal to 0') unless o >= 0 711 end 712 clone(:offset => o) 713 end
Adds an alternate filter to an existing WHERE clause using OR. If there is no WHERE clause, then the default is WHERE true, and OR would be redundant, so return the dataset in that case.
DB[:items].where(:a).or(:b) # SELECT * FROM items WHERE a OR b DB[:items].or(:b) # SELECT * FROM items
# File lib/sequel/dataset/query.rb 721 def or(*cond, &block) 722 if @opts[:where].nil? 723 self 724 else 725 add_filter(:where, cond, false, :OR, &block) 726 end 727 end
Returns a copy of the dataset with the order changed. If the dataset has an existing order, it is ignored and overwritten with this order. If a nil is given the returned dataset has no order. This can accept multiple arguments of varying kinds, such as SQL
functions. If a block is given, it is treated as a virtual row block, similar to where
.
DB[:items].order(:name) # SELECT * FROM items ORDER BY name DB[:items].order(:a, :b) # SELECT * FROM items ORDER BY a, b DB[:items].order(Sequel.lit('a + b')) # SELECT * FROM items ORDER BY a + b DB[:items].order(Sequel[:a] + :b) # SELECT * FROM items ORDER BY (a + b) DB[:items].order(Sequel.desc(:name)) # SELECT * FROM items ORDER BY name DESC DB[:items].order(Sequel.asc(:name, :nulls=>:last)) # SELECT * FROM items ORDER BY name ASC NULLS LAST DB[:items].order{sum(name).desc} # SELECT * FROM items ORDER BY sum(name) DESC DB[:items].order(nil) # SELECT * FROM items
# File lib/sequel/dataset/query.rb 743 def order(*columns, &block) 744 virtual_row_columns(columns, block) 745 clone(:order => (columns.compact.empty?) ? nil : columns.freeze) 746 end
Returns a copy of the dataset with the order columns added to the end of the existing order.
DB[:items].order(:a).order(:b) # SELECT * FROM items ORDER BY b DB[:items].order(:a).order_append(:b) # SELECT * FROM items ORDER BY a, b
# File lib/sequel/dataset/query.rb 753 def order_append(*columns, &block) 754 columns = @opts[:order] + columns if @opts[:order] 755 order(*columns, &block) 756 end
Alias of order
# File lib/sequel/dataset/query.rb 759 def order_by(*columns, &block) 760 order(*columns, &block) 761 end
Alias of order_append.
# File lib/sequel/dataset/query.rb 764 def order_more(*columns, &block) 765 order_append(*columns, &block) 766 end
Returns a copy of the dataset with the order columns added to the beginning of the existing order.
DB[:items].order(:a).order(:b) # SELECT * FROM items ORDER BY b DB[:items].order(:a).order_prepend(:b) # SELECT * FROM items ORDER BY b, a
# File lib/sequel/dataset/query.rb 773 def order_prepend(*columns, &block) 774 ds = order(*columns, &block) 775 @opts[:order] ? ds.order_append(*@opts[:order]) : ds 776 end
Qualify to the given table, or first source if no table is given.
DB[:items].where(id: 1).qualify # SELECT items.* FROM items WHERE (items.id = 1) DB[:items].where(id: 1).qualify(:i) # SELECT i.* FROM items WHERE (i.id = 1)
# File lib/sequel/dataset/query.rb 785 def qualify(table=(cache=true; first_source)) 786 o = @opts 787 return self if o[:sql] 788 789 pr = proc do 790 h = {} 791 (o.keys & QUALIFY_KEYS).each do |k| 792 h[k] = qualified_expression(o[k], table) 793 end 794 h[:select] = [SQL::ColumnAll.new(table)].freeze if !o[:select] || o[:select].empty? 795 clone(h) 796 end 797 798 cache ? cached_dataset(:_qualify_ds, &pr) : pr.call 799 end
Modify the RETURNING clause, only supported on a few databases. If returning is used, instead of insert returning the autogenerated primary key or update/delete returning the number of modified rows, results are returned using fetch_rows
.
DB[:items].returning # RETURNING * DB[:items].returning(nil) # RETURNING NULL DB[:items].returning(:id, :name) # RETURNING id, name DB[:items].returning.insert(:a=>1) do |hash| # hash for each row inserted, with values for all columns end DB[:items].returning.update(:a=>1) do |hash| # hash for each row updated, with values for all columns end DB[:items].returning.delete(:a=>1) do |hash| # hash for each row deleted, with values for all columns end
# File lib/sequel/dataset/query.rb 819 def returning(*values) 820 if values.empty? 821 cached_dataset(:_returning_ds) do 822 raise Error, "RETURNING is not supported on #{db.database_type}" unless supports_returning?(:insert) 823 clone(:returning=>EMPTY_ARRAY) 824 end 825 else 826 raise Error, "RETURNING is not supported on #{db.database_type}" unless supports_returning?(:insert) 827 clone(:returning=>values.freeze) 828 end 829 end
Returns a copy of the dataset with the order reversed. If no order is given, the existing order is inverted.
DB[:items].reverse(:id) # SELECT * FROM items ORDER BY id DESC DB[:items].reverse{foo(bar)} # SELECT * FROM items ORDER BY foo(bar) DESC DB[:items].order(:id).reverse # SELECT * FROM items ORDER BY id DESC DB[:items].order(:id).reverse(Sequel.desc(:name)) # SELECT * FROM items ORDER BY name ASC
# File lib/sequel/dataset/query.rb 838 def reverse(*order, &block) 839 if order.empty? && !block 840 cached_dataset(:_reverse_ds){order(*invert_order(@opts[:order]))} 841 else 842 virtual_row_columns(order, block) 843 order(*invert_order(order.empty? ? @opts[:order] : order.freeze)) 844 end 845 end
Alias of reverse
# File lib/sequel/dataset/query.rb 848 def reverse_order(*order, &block) 849 reverse(*order, &block) 850 end
Returns a copy of the dataset with the columns selected changed to the given columns. This also takes a virtual row block, similar to where
.
DB[:items].select(:a) # SELECT a FROM items DB[:items].select(:a, :b) # SELECT a, b FROM items DB[:items].select{[a, sum(b)]} # SELECT a, sum(b) FROM items
# File lib/sequel/dataset/query.rb 859 def select(*columns, &block) 860 virtual_row_columns(columns, block) 861 clone(:select => columns.freeze) 862 end
Returns a copy of the dataset selecting the wildcard if no arguments are given. If arguments are given, treat them as tables and select all columns (using the wildcard) from each table.
DB[:items].select(:a).select_all # SELECT * FROM items DB[:items].select_all(:items) # SELECT items.* FROM items DB[:items].select_all(:items, :foo) # SELECT items.*, foo.* FROM items
# File lib/sequel/dataset/query.rb 871 def select_all(*tables) 872 if tables.empty? 873 cached_dataset(:_select_all_ds){clone(:select => nil)} 874 else 875 select(*tables.map{|t| i, a = split_alias(t); a || i}.map!{|t| SQL::ColumnAll.new(t)}.freeze) 876 end 877 end
Returns a copy of the dataset with the given columns added to the existing selected columns. If no columns are currently selected, it will select the columns given in addition to *.
DB[:items].select(:a).select(:b) # SELECT b FROM items DB[:items].select(:a).select_append(:b) # SELECT a, b FROM items DB[:items].select_append(:b) # SELECT *, b FROM items
# File lib/sequel/dataset/query.rb 886 def select_append(*columns, &block) 887 cur_sel = @opts[:select] 888 if !cur_sel || cur_sel.empty? 889 unless supports_select_all_and_column? 890 return select_all(*(Array(@opts[:from]) + Array(@opts[:join]))).select_append(*columns, &block) 891 end 892 cur_sel = [WILDCARD] 893 end 894 select(*(cur_sel + columns), &block) 895 end
Set both the select and group clauses with the given columns
. Column aliases may be supplied, and will be included in the select clause. This also takes a virtual row block similar to where
.
DB[:items].select_group(:a, :b) # SELECT a, b FROM items GROUP BY a, b DB[:items].select_group(Sequel[:c].as(:a)){f(c2)} # SELECT c AS a, f(c2) FROM items GROUP BY c, f(c2)
# File lib/sequel/dataset/query.rb 906 def select_group(*columns, &block) 907 virtual_row_columns(columns, block) 908 select(*columns).group(*columns.map{|c| unaliased_identifier(c)}) 909 end
Alias for select_append.
# File lib/sequel/dataset/query.rb 912 def select_more(*columns, &block) 913 select_append(*columns, &block) 914 end
Set the server for this dataset to use. Used to pick a specific database shard to run a query against, or to override the default (where SELECT uses :read_only database and all other queries use the :default database). This method is always available but is only useful when database sharding is being used.
DB[:items].all # Uses the :read_only or :default server DB[:items].delete # Uses the :default server DB[:items].server(:blah).delete # Uses the :blah server
# File lib/sequel/dataset/query.rb 925 def server(servr) 926 clone(:server=>servr) 927 end
If the database uses sharding and the current dataset has not had a server set, return a cloned dataset that uses the given server. Otherwise, return the receiver directly instead of returning a clone.
# File lib/sequel/dataset/query.rb 932 def server?(server) 933 if db.sharded? && !opts[:server] 934 server(server) 935 else 936 self 937 end 938 end
Specify that the check for limits/offsets when updating/deleting be skipped for the dataset.
# File lib/sequel/dataset/query.rb 941 def skip_limit_check 942 cached_dataset(:_skip_limit_check_ds) do 943 clone(:skip_limit_check=>true) 944 end 945 end
Skip locked rows when returning results from this dataset.
# File lib/sequel/dataset/query.rb 948 def skip_locked 949 cached_dataset(:_skip_locked_ds) do 950 raise(Error, 'This dataset does not support skipping locked rows') unless supports_skip_locked? 951 clone(:skip_locked=>true) 952 end 953 end
Returns a copy of the dataset with no filters (HAVING or WHERE clause) applied.
DB[:items].group(:a).having(a: 1).where(:b).unfiltered # SELECT * FROM items GROUP BY a
# File lib/sequel/dataset/query.rb 959 def unfiltered 960 cached_dataset(:_unfiltered_ds){clone(:where => nil, :having => nil)} 961 end
Returns a copy of the dataset with no grouping (GROUP or HAVING clause) applied.
DB[:items].group(:a).having(a: 1).where(:b).ungrouped # SELECT * FROM items WHERE b
# File lib/sequel/dataset/query.rb 967 def ungrouped 968 cached_dataset(:_ungrouped_ds){clone(:group => nil, :having => nil)} 969 end
Adds a UNION clause using a second dataset object. A UNION compound dataset returns all rows in either the current dataset or the given dataset. Options:
- :alias
-
Use the given value as the
from_self
alias - :all
-
Set to true to use UNION ALL instead of UNION, so duplicate rows can occur
- :from_self
-
Set to false to not wrap the returned dataset in a
from_self
, use with care.
DB[:items].union(DB[:other_items]) # SELECT * FROM (SELECT * FROM items UNION SELECT * FROM other_items) AS t1 DB[:items].union(DB[:other_items], all: true, from_self: false) # SELECT * FROM items UNION ALL SELECT * FROM other_items DB[:items].union(DB[:other_items], alias: :i) # SELECT * FROM (SELECT * FROM items UNION SELECT * FROM other_items) AS i
# File lib/sequel/dataset/query.rb 987 def union(dataset, opts=OPTS) 988 compound_clone(:union, dataset, opts) 989 end
Returns a copy of the dataset with no limit or offset.
DB[:items].limit(10, 20).unlimited # SELECT * FROM items
# File lib/sequel/dataset/query.rb 994 def unlimited 995 cached_dataset(:_unlimited_ds){clone(:limit=>nil, :offset=>nil)} 996 end
Returns a copy of the dataset with no order.
DB[:items].order(:a).unordered # SELECT * FROM items
# File lib/sequel/dataset/query.rb 1001 def unordered 1002 cached_dataset(:_unordered_ds){clone(:order=>nil)} 1003 end
Returns a copy of the dataset with the given WHERE conditions imposed upon it.
Accepts the following argument types:
Hash
,Array
of pairs-
list of equality/inclusion expressions
Symbol
-
taken as a boolean column argument (e.g. WHERE active)
Sequel::SQL::BooleanExpression
,Sequel::LiteralString
-
an existing condition expression, probably created using the
Sequel
expression filter DSL.
where also accepts a block, which should return one of the above argument types, and is treated the same way. This block yields a virtual row object, which is easy to use to create identifiers and functions. For more details on the virtual row support, see the “Virtual Rows” guide
If both a block and regular argument are provided, they get ANDed together.
Examples:
DB[:items].where(id: 3) # SELECT * FROM items WHERE (id = 3) DB[:items].where(Sequel.lit('price < ?', 100)) # SELECT * FROM items WHERE price < 100 DB[:items].where([[:id, [1,2,3]], [:id, 0..10]]) # SELECT * FROM items WHERE ((id IN (1, 2, 3)) AND ((id >= 0) AND (id <= 10))) DB[:items].where(Sequel.lit('price < 100')) # SELECT * FROM items WHERE price < 100 DB[:items].where(:active) # SELECT * FROM items WHERE :active DB[:items].where{price < 100} # SELECT * FROM items WHERE (price < 100)
Multiple where calls can be chained for scoping:
software = dataset.where(category: 'software').where{price < 100} # SELECT * FROM items WHERE ((category = 'software') AND (price < 100))
See the “Dataset Filtering” guide for more examples and details.
# File lib/sequel/dataset/query.rb 1047 def where(*cond, &block) 1048 add_filter(:where, cond, &block) 1049 end
Return a clone of the dataset with an addition named window that can be referenced in window functions. See Sequel::SQL::Window
for a list of options that can be passed in. Example:
DB[:items].window(:w, :partition=>:c1, :order=>:c2) # SELECT * FROM items WINDOW w AS (PARTITION BY c1 ORDER BY c2)
# File lib/sequel/dataset/query.rb 1057 def window(name, opts) 1058 clone(:window=>((@opts[:window]||EMPTY_ARRAY) + [[name, SQL::Window.new(opts)].freeze]).freeze) 1059 end
Add a common table expression (CTE) with the given name and a dataset that defines the CTE. A common table expression acts as an inline view for the query.
Options:
- :args
-
Specify the arguments/columns for the CTE, should be an array of symbols.
- :recursive
-
Specify that this is a recursive CTE
- :materialized
-
Set to false to force inlining of the CTE, or true to force not inlining the CTE (PostgreSQL 12+/SQLite 3.35+).
DB[:items].with(:items, DB[:syx].where(Sequel[:name].like('A%'))) # WITH items AS (SELECT * FROM syx WHERE (name LIKE 'A%' ESCAPE '\')) SELECT * FROM items
# File lib/sequel/dataset/query.rb 1072 def with(name, dataset, opts=OPTS) 1073 raise(Error, 'This dataset does not support common table expressions') unless supports_cte? 1074 if hoist_cte?(dataset) 1075 s, ds = hoist_cte(dataset) 1076 s.with(name, ds, opts) 1077 else 1078 clone(:with=>((@opts[:with]||EMPTY_ARRAY) + [Hash[opts].merge!(:name=>name, :dataset=>dataset)]).freeze) 1079 end 1080 end
Return a clone of the dataset extended with the given modules. Note that like Object#extend, when multiple modules are provided as arguments the cloned dataset is extended with the modules in reverse order. If a block is provided, a DatasetModule
is created using the block and the clone is extended with that module after any modules given as arguments.
# File lib/sequel/dataset/query.rb 1157 def with_extend(*mods, &block) 1158 c = _clone(:freeze=>false) 1159 c.extend(*mods) unless mods.empty? 1160 c.extend(DatasetModule.new(&block)) if block 1161 c.freeze 1162 end
Add a recursive common table expression (CTE) with the given name, a dataset that defines the nonrecursive part of the CTE, and a dataset that defines the recursive part of the CTE.
Options:
- :args
-
Specify the arguments/columns for the CTE, should be an array of symbols.
- :union_all
-
Set to false to use UNION instead of UNION ALL combining the nonrecursive and recursive parts.
PostgreSQL 14+ Options:
- :cycle
-
Stop recursive searching when a cycle is detected. Includes two columns in the result of the CTE, a cycle column indicating whether a cycle was detected for the current row, and a path column for the path traversed to get to the current row. If given, must be a hash with the following keys:
- :columns
-
(required) The column or array of columns to use to detect a cycle. If the value of these columns match columns already traversed, then a cycle is detected, and recursive searching will not traverse beyond the cycle (the CTE will include the row where the cycle was detected).
- :cycle_column
-
The name of the cycle column in the output, defaults to :is_cycle.
- :cycle_value
-
The value of the cycle column in the output if the current row was detected as a cycle, defaults to true.
- :noncycle_value
-
The value of the cycle column in the output if the current row was not detected as a cycle, defaults to false. Only respected if :cycle_value is given.
- :path_column
-
The name of the path column in the output, defaults to :path.
- :search
-
Include an order column in the result of the CTE that allows for breadth or depth first searching. If given, must be a hash with the following keys:
- :by
-
(required) The column or array of columns to search by.
- :order_column
-
The name of the order column in the output, defaults to :ordercol.
- :type
-
Set to :breadth to use breadth-first searching (depth-first searching is the default).
DB[:t].with_recursive(:t, DB[:i1].select(:id, :parent_id).where(parent_id: nil), DB[:i1].join(:t, id: :parent_id).select(Sequel[:i1][:id], Sequel[:i1][:parent_id]), :args=>[:id, :parent_id]) # WITH RECURSIVE t(id, parent_id) AS ( # SELECT id, parent_id FROM i1 WHERE (parent_id IS NULL) # UNION ALL # SELECT i1.id, i1.parent_id FROM i1 INNER JOIN t ON (t.id = i1.parent_id) # ) SELECT * FROM t DB[:t].with_recursive(:t, DB[:i1].where(parent_id: nil), DB[:i1].join(:t, id: :parent_id).select_all(:i1), search: {by: :id, type: :breadth}, cycle: {columns: :id, cycle_value: 1, noncycle_value: 2}) # WITH RECURSIVE t AS ( # SELECT * FROM i1 WHERE (parent_id IS NULL) # UNION ALL # (SELECT i1.* FROM i1 INNER JOIN t ON (t.id = i1.parent_id)) # ) # SEARCH BREADTH FIRST BY id SET ordercol # CYCLE id SET is_cycle TO 1 DEFAULT 2 USING path # SELECT * FROM t
# File lib/sequel/dataset/query.rb 1138 def with_recursive(name, nonrecursive, recursive, opts=OPTS) 1139 raise(Error, 'This dataset does not support common table expressions') unless supports_cte? 1140 if hoist_cte?(nonrecursive) 1141 s, ds = hoist_cte(nonrecursive) 1142 s.with_recursive(name, ds, recursive, opts) 1143 elsif hoist_cte?(recursive) 1144 s, ds = hoist_cte(recursive) 1145 s.with_recursive(name, nonrecursive, ds, opts) 1146 else 1147 clone(:with=>((@opts[:with]||EMPTY_ARRAY) + [Hash[opts].merge!(:recursive=>true, :name=>name, :dataset=>nonrecursive.union(recursive, {:all=>opts[:union_all] != false, :from_self=>false}))]).freeze) 1148 end 1149 end
Returns a cloned dataset with the given row_proc.
ds = DB[:items] ds.all # => [{:id=>2}] ds.with_row_proc(:invert.to_proc).all # => [{2=>:id}]
# File lib/sequel/dataset/query.rb 1179 def with_row_proc(callable) 1180 clone(:row_proc=>callable) 1181 end
Returns a copy of the dataset with the static SQL
used. This is useful if you want to keep the same row_proc/graph, but change the SQL
used to custom SQL
.
DB[:items].with_sql('SELECT * FROM foo') # SELECT * FROM foo
You can use placeholders in your SQL
and provide arguments for those placeholders:
DB[:items].with_sql('SELECT ? FROM foo', 1) # SELECT 1 FROM foo
You can also provide a method name and arguments to call to get the SQL:
DB[:items].with_sql(:insert_sql, :b=>1) # INSERT INTO items (b) VALUES (1)
Note that datasets that specify custom SQL
using this method will generally ignore future dataset methods that modify the SQL
used, as specifying custom SQL
overrides Sequel’s SQL
generator. You should probably limit yourself to the following dataset methods when using this method, or use the implicit_subquery extension:
-
each
-
all
-
single_record
(if only one record could be returned) -
single_value
(if only one record could be returned, and a single column is selected) -
map
-
delete (if a DELETE statement)
-
update (if an UPDATE statement, with no arguments)
-
insert (if an INSERT statement, with no arguments)
-
truncate (if a TRUNCATE statement, with no arguments)
# File lib/sequel/dataset/query.rb 1213 def with_sql(sql, *args) 1214 if sql.is_a?(Symbol) 1215 sql = public_send(sql, *args) 1216 else 1217 sql = SQL::PlaceholderLiteralString.new(sql, args) unless args.empty? 1218 end 1219 clone(:sql=>sql) 1220 end
Protected Instance Methods
Add the dataset to the list of compounds
# File lib/sequel/dataset/query.rb 1225 def compound_clone(type, dataset, opts) 1226 if dataset.is_a?(Dataset) && dataset.opts[:with] && !supports_cte_in_compounds? 1227 s, ds = hoist_cte(dataset) 1228 return s.compound_clone(type, ds, opts) 1229 end 1230 ds = compound_from_self.clone(:compounds=>(Array(@opts[:compounds]).map(&:dup) + [[type, dataset.compound_from_self, opts[:all]].freeze]).freeze) 1231 opts[:from_self] == false ? ds : ds.from_self(opts) 1232 end
Return true if the dataset has a non-nil value for any key in opts.
# File lib/sequel/dataset/query.rb 1235 def options_overlap(opts) 1236 !(@opts.map{|k,v| k unless v.nil?}.compact & opts).empty? 1237 end
Whether this dataset is a simple select from an underlying table, such as:
SELECT * FROM table SELECT table.* FROM table
# File lib/sequel/dataset/query.rb 1246 def simple_select_all? 1247 return false unless (f = @opts[:from]) && f.length == 1 1248 o = @opts.reject{|k,v| v.nil? || non_sql_option?(k)} 1249 from = f.first 1250 from = from.expression if from.is_a?(SQL::AliasedExpression) 1251 1252 if SIMPLE_SELECT_ALL_ALLOWED_FROM.any?{|x| from.is_a?(x)} 1253 case o.length 1254 when 1 1255 true 1256 when 2 1257 (s = o[:select]) && s.length == 1 && s.first.is_a?(SQL::ColumnAll) 1258 else 1259 false 1260 end 1261 else 1262 false 1263 end 1264 end
Private Instance Methods
Load the extensions into the receiver, without checking if the receiver is frozen.
# File lib/sequel/dataset/query.rb 1269 def _extension!(exts) 1270 Sequel.extension(*exts) 1271 exts.each do |ext| 1272 if pr = Sequel.synchronize{EXTENSIONS[ext]} 1273 pr.call(self) 1274 else 1275 raise(Error, "Extension #{ext} does not have specific support handling individual datasets (try: Sequel.extension #{ext.inspect})") 1276 end 1277 end 1278 self 1279 end
If invert is true, invert the condition.
# File lib/sequel/dataset/query.rb 1282 def _invert_filter(cond, invert) 1283 if invert 1284 SQL::BooleanExpression.invert(cond) 1285 else 1286 cond 1287 end 1288 end
Add the given filter condition. Arguments:
- clause
-
Symbol
or whichSQL
clause to effect, should be :where or :having - cond
-
The filter condition to add
- invert
-
Whether the condition should be inverted (true or false)
- combine
-
How to combine the condition with an existing condition, should be :AND or :OR
# File lib/sequel/dataset/query.rb 1295 def add_filter(clause, cond, invert=false, combine=:AND, &block) 1296 if cond == EMPTY_ARRAY && !block 1297 raise Error, "must provide an argument to a filtering method if not passing a block" 1298 end 1299 1300 cond = cond.first if cond.size == 1 1301 1302 empty = cond == OPTS || cond == EMPTY_ARRAY 1303 1304 if empty && !block 1305 self 1306 else 1307 if cond == nil 1308 cond = Sequel::NULL 1309 end 1310 if empty && block 1311 cond = nil 1312 end 1313 1314 cond = _invert_filter(filter_expr(cond, &block), invert) 1315 cond = SQL::BooleanExpression.new(combine, @opts[clause], cond) if @opts[clause] 1316 1317 if cond.nil? 1318 cond = Sequel::NULL 1319 end 1320 1321 clone(clause => cond) 1322 end 1323 end
The default :qualify option to use for join tables if one is not specified.
# File lib/sequel/dataset/query.rb 1326 def default_join_table_qualification 1327 :symbol 1328 end
Return self if the dataset already has a server, or a cloned dataset with the default server otherwise.
# File lib/sequel/dataset/query.rb 1401 def default_server 1402 server?(:default) 1403 end
SQL
expression object based on the expr type. See where
.
# File lib/sequel/dataset/query.rb 1331 def filter_expr(expr = nil, &block) 1332 expr = nil if expr == EMPTY_ARRAY 1333 1334 if block 1335 cond = filter_expr(Sequel.virtual_row(&block)) 1336 cond = SQL::BooleanExpression.new(:AND, filter_expr(expr), cond) if expr 1337 return cond 1338 end 1339 1340 case expr 1341 when Hash 1342 SQL::BooleanExpression.from_value_pairs(expr) 1343 when Array 1344 if Sequel.condition_specifier?(expr) 1345 SQL::BooleanExpression.from_value_pairs(expr) 1346 else 1347 raise Error, "Invalid filter expression: #{expr.inspect}" 1348 end 1349 when LiteralString 1350 LiteralString.new("(#{expr})") 1351 when Numeric, SQL::NumericExpression, SQL::StringExpression, Proc, String 1352 raise Error, "Invalid filter expression: #{expr.inspect}" 1353 when TrueClass, FalseClass 1354 if supports_where_true? 1355 SQL::BooleanExpression.new(:NOOP, expr) 1356 elsif expr 1357 SQL::Constants::SQLTRUE 1358 else 1359 SQL::Constants::SQLFALSE 1360 end 1361 when PlaceholderLiteralizer::Argument 1362 expr.transform{|v| filter_expr(v)} 1363 when SQL::PlaceholderLiteralString 1364 expr.with_parens 1365 else 1366 expr 1367 end 1368 end
Return two datasets, the first a clone of the receiver with the WITH clause from the given dataset added to it, and the second a clone of the given dataset with the WITH clause removed.
# File lib/sequel/dataset/query.rb 1373 def hoist_cte(ds) 1374 [clone(:with => ((opts[:with] || EMPTY_ARRAY) + ds.opts[:with]).freeze), ds.clone(:with => nil)] 1375 end
Whether CTEs need to be hoisted from the given ds into the current ds.
# File lib/sequel/dataset/query.rb 1378 def hoist_cte?(ds) 1379 ds.is_a?(Dataset) && ds.opts[:with] && !supports_cte_in_subqueries? 1380 end
Inverts the given order by breaking it into a list of column references and inverting them.
DB[:items].invert_order([Sequel.desc(:id)]]) #=> [Sequel.asc(:id)] DB[:items].invert_order([:category, Sequel.desc(:price)]) #=> [Sequel.desc(:category), Sequel.asc(:price)]
# File lib/sequel/dataset/query.rb 1387 def invert_order(order) 1388 return unless order 1389 order.map do |f| 1390 case f 1391 when SQL::OrderedExpression 1392 f.invert 1393 else 1394 SQL::OrderedExpression.new(f) 1395 end 1396 end 1397 end
Whether the given option key does not affect the generated SQL
.
# File lib/sequel/dataset/query.rb 1406 def non_sql_option?(key) 1407 NON_SQL_OPTIONS.include?(key) 1408 end
Treat the block
as a virtual_row block if not nil
and add the resulting columns to the columns
array (modifies columns
).
# File lib/sequel/dataset/query.rb 1412 def virtual_row_columns(columns, block) 1413 if block 1414 v = Sequel.virtual_row(&block) 1415 if v.is_a?(Array) 1416 columns.concat(v) 1417 else 1418 columns << v 1419 end 1420 end 1421 end
2 - Methods that execute code on the database
↑ topConstants
- ACTION_METHODS
Action methods defined by
Sequel
that execute code on the database.- COLUMNS_CLONE_OPTIONS
The clone options to use when retrieving columns for a dataset.
- COUNT_SELECT
- EMPTY_SELECT
Public Instance Methods
Inserts the given argument into the database. Returns self so it can be used safely when chaining:
DB[:items] << {id: 0, name: 'Zero'} << DB[:old_items].select(:id, name)
# File lib/sequel/dataset/actions.rb 28 def <<(arg) 29 insert(arg) 30 self 31 end
Returns the first record matching the conditions. Examples:
DB[:table][id: 1] # SELECT * FROM table WHERE (id = 1) LIMIT 1 # => {:id=>1}
# File lib/sequel/dataset/actions.rb 37 def [](*conditions) 38 raise(Error, 'You cannot call Dataset#[] with an integer or with no arguments') if (conditions.length == 1 and conditions.first.is_a?(Integer)) or conditions.length == 0 39 first(*conditions) 40 end
Returns an array with all records in the dataset. If a block is given, the array is iterated over after all items have been loaded.
DB[:table].all # SELECT * FROM table # => [{:id=>1, ...}, {:id=>2, ...}, ...] # Iterate over all rows in the table DB[:table].all{|row| p row}
# File lib/sequel/dataset/actions.rb 50 def all(&block) 51 _all(block){|a| each{|r| a << r}} 52 end
Returns a hash with one column used as key and another used as value. If rows have duplicate values for the key column, the latter row(s) will overwrite the value of the previous row(s). If the value_column is not given or nil, uses the entire hash as the value.
DB[:table].as_hash(:id, :name) # SELECT * FROM table # {1=>'Jim', 2=>'Bob', ...} DB[:table].as_hash(:id) # SELECT * FROM table # {1=>{:id=>1, :name=>'Jim'}, 2=>{:id=>2, :name=>'Bob'}, ...}
You can also provide an array of column names for either the key_column, the value column, or both:
DB[:table].as_hash([:id, :foo], [:name, :bar]) # SELECT * FROM table # {[1, 3]=>['Jim', 'bo'], [2, 4]=>['Bob', 'be'], ...} DB[:table].as_hash([:id, :name]) # SELECT * FROM table # {[1, 'Jim']=>{:id=>1, :name=>'Jim'}, [2, 'Bob']=>{:id=>2, :name=>'Bob'}, ...}
Options:
- :all
-
Use all instead of each to retrieve the objects
- :hash
-
The object into which the values will be placed. If this is not given, an empty hash is used. This can be used to use a hash with a default value or default proc.
# File lib/sequel/dataset/actions.rb 774 def as_hash(key_column, value_column = nil, opts = OPTS) 775 h = opts[:hash] || {} 776 meth = opts[:all] ? :all : :each 777 if value_column 778 return naked.as_hash(key_column, value_column, opts) if row_proc 779 if value_column.is_a?(Array) 780 if key_column.is_a?(Array) 781 public_send(meth){|r| h[r.values_at(*key_column)] = r.values_at(*value_column)} 782 else 783 public_send(meth){|r| h[r[key_column]] = r.values_at(*value_column)} 784 end 785 else 786 if key_column.is_a?(Array) 787 public_send(meth){|r| h[r.values_at(*key_column)] = r[value_column]} 788 else 789 public_send(meth){|r| h[r[key_column]] = r[value_column]} 790 end 791 end 792 elsif key_column.is_a?(Array) 793 public_send(meth){|r| h[key_column.map{|k| r[k]}] = r} 794 else 795 public_send(meth){|r| h[r[key_column]] = r} 796 end 797 h 798 end
Returns the average value for the given column/expression. Uses a virtual row block if no argument is given.
DB[:table].avg(:number) # SELECT avg(number) FROM table LIMIT 1 # => 3 DB[:table].avg{function(column)} # SELECT avg(function(column)) FROM table LIMIT 1 # => 1
# File lib/sequel/dataset/actions.rb 61 def avg(arg=(no_arg = true), &block) 62 arg = Sequel.virtual_row(&block) if no_arg 63 _aggregate(:avg, arg) 64 end
Returns the columns in the result set in order as an array of symbols. If the columns are currently cached, returns the cached value. Otherwise, a SELECT query is performed to retrieve a single row in order to get the columns.
If you are looking for all columns for a single table and maybe some information about each column (e.g. database type), see Database#schema
.
DB[:table].columns # => [:id, :name]
# File lib/sequel/dataset/actions.rb 75 def columns 76 _columns || columns! 77 end
Ignore any cached column information and perform a query to retrieve a row in order to get the columns.
DB[:table].columns! # => [:id, :name]
# File lib/sequel/dataset/actions.rb 84 def columns! 85 ds = clone(COLUMNS_CLONE_OPTIONS) 86 ds.each{break} 87 88 if cols = ds.cache[:_columns] 89 self.columns = cols 90 else 91 [] 92 end 93 end
Returns the number of records in the dataset. If an argument is provided, it is used as the argument to count. If a block is provided, it is treated as a virtual row, and the result is used as the argument to count.
DB[:table].count # SELECT count(*) AS count FROM table LIMIT 1 # => 3 DB[:table].count(:column) # SELECT count(column) AS count FROM table LIMIT 1 # => 2 DB[:table].count{foo(column)} # SELECT count(foo(column)) AS count FROM table LIMIT 1 # => 1
# File lib/sequel/dataset/actions.rb 108 def count(arg=(no_arg=true), &block) 109 if no_arg && !block 110 cached_dataset(:_count_ds) do 111 aggregate_dataset.select(COUNT_SELECT).single_value_ds 112 end.single_value!.to_i 113 else 114 if block 115 if no_arg 116 arg = Sequel.virtual_row(&block) 117 else 118 raise Error, 'cannot provide both argument and block to Dataset#count' 119 end 120 end 121 122 _aggregate(:count, arg) 123 end 124 end
Deletes the records in the dataset, returning the number of records deleted.
DB[:table].delete # DELETE * FROM table # => 3
# File lib/sequel/dataset/actions.rb 130 def delete(&block) 131 sql = delete_sql 132 if uses_returning?(:delete) 133 returning_fetch_rows(sql, &block) 134 else 135 execute_dui(sql) 136 end 137 end
Iterates over the records in the dataset as they are yielded from the database adapter, and returns self.
DB[:table].each{|row| p row} # SELECT * FROM table
Note that this method is not safe to use on many adapters if you are running additional queries inside the provided block. If you are running queries inside the block, you should use all
instead of each
for the outer queries, or use a separate thread or shard inside each
.
# File lib/sequel/dataset/actions.rb 148 def each 149 if rp = row_proc 150 fetch_rows(select_sql){|r| yield rp.call(r)} 151 else 152 fetch_rows(select_sql){|r| yield r} 153 end 154 self 155 end
Returns true if no records exist in the dataset, false otherwise
DB[:table].empty? # SELECT 1 AS one FROM table LIMIT 1 # => false
# File lib/sequel/dataset/actions.rb 163 def empty? 164 cached_dataset(:_empty_ds) do 165 single_value_ds.unordered.select(EMPTY_SELECT) 166 end.single_value!.nil? 167 end
Returns the first matching record if no arguments are given. If a integer argument is given, it is interpreted as a limit, and then returns all matching records up to that limit. If any other type of argument(s) is passed, it is treated as a filter and the first matching record is returned. If a block is given, it is used to filter the dataset before returning anything.
If there are no records in the dataset, returns nil (or an empty array if an integer argument is given).
Examples:
DB[:table].first # SELECT * FROM table LIMIT 1 # => {:id=>7} DB[:table].first(2) # SELECT * FROM table LIMIT 2 # => [{:id=>6}, {:id=>4}] DB[:table].first(id: 2) # SELECT * FROM table WHERE (id = 2) LIMIT 1 # => {:id=>2} DB[:table].first(Sequel.lit("id = 3")) # SELECT * FROM table WHERE (id = 3) LIMIT 1 # => {:id=>3} DB[:table].first(Sequel.lit("id = ?", 4)) # SELECT * FROM table WHERE (id = 4) LIMIT 1 # => {:id=>4} DB[:table].first{id > 2} # SELECT * FROM table WHERE (id > 2) LIMIT 1 # => {:id=>5} DB[:table].first(Sequel.lit("id > ?", 4)){id < 6} # SELECT * FROM table WHERE ((id > 4) AND (id < 6)) LIMIT 1 # => {:id=>5} DB[:table].first(2){id < 2} # SELECT * FROM table WHERE (id < 2) LIMIT 2 # => [{:id=>1}]
# File lib/sequel/dataset/actions.rb 204 def first(*args, &block) 205 case args.length 206 when 0 207 unless block 208 return single_record 209 end 210 when 1 211 arg = args[0] 212 if arg.is_a?(Integer) 213 res = if block 214 if loader = cached_placeholder_literalizer(:_first_integer_cond_loader) do |pl| 215 where(pl.arg).limit(pl.arg) 216 end 217 218 loader.all(filter_expr(&block), arg) 219 else 220 where(&block).limit(arg).all 221 end 222 else 223 if loader = cached_placeholder_literalizer(:_first_integer_loader) do |pl| 224 limit(pl.arg) 225 end 226 227 loader.all(arg) 228 else 229 limit(arg).all 230 end 231 end 232 233 return res 234 end 235 where_args = args 236 args = arg 237 end 238 239 if loader = cached_where_placeholder_literalizer(where_args||args, block, :_first_cond_loader) do |pl| 240 _single_record_ds.where(pl.arg) 241 end 242 243 loader.first(filter_expr(args, &block)) 244 else 245 _single_record_ds.where(args, &block).single_record! 246 end 247 end
Calls first. If first returns nil (signaling that no row matches), raise a Sequel::NoMatchingRow
exception.
# File lib/sequel/dataset/actions.rb 251 def first!(*args, &block) 252 first(*args, &block) || raise(Sequel::NoMatchingRow.new(self)) 253 end
Return the column value for the first matching record in the dataset. Raises an error if both an argument and block is given.
DB[:table].get(:id) # SELECT id FROM table LIMIT 1 # => 3 ds.get{sum(id)} # SELECT sum(id) AS v FROM table LIMIT 1 # => 6
You can pass an array of arguments to return multiple arguments, but you must make sure each element in the array has an alias that Sequel
can determine:
DB[:table].get([:id, :name]) # SELECT id, name FROM table LIMIT 1 # => [3, 'foo'] DB[:table].get{[sum(id).as(sum), name]} # SELECT sum(id) AS sum, name FROM table LIMIT 1 # => [6, 'foo']
# File lib/sequel/dataset/actions.rb 273 def get(column=(no_arg=true; nil), &block) 274 ds = naked 275 if block 276 raise(Error, 'Must call Dataset#get with an argument or a block, not both') unless no_arg 277 ds = ds.select(&block) 278 column = ds.opts[:select] 279 column = nil if column.is_a?(Array) && column.length < 2 280 else 281 case column 282 when Array 283 ds = ds.select(*column) 284 when LiteralString, Symbol, SQL::Identifier, SQL::QualifiedIdentifier, SQL::AliasedExpression 285 if loader = cached_placeholder_literalizer(:_get_loader) do |pl| 286 ds.single_value_ds.select(pl.arg) 287 end 288 289 return loader.get(column) 290 end 291 292 ds = ds.select(column) 293 else 294 if loader = cached_placeholder_literalizer(:_get_alias_loader) do |pl| 295 ds.single_value_ds.select(Sequel.as(pl.arg, :v)) 296 end 297 298 return loader.get(column) 299 end 300 301 ds = ds.select(Sequel.as(column, :v)) 302 end 303 end 304 305 if column.is_a?(Array) 306 if r = ds.single_record 307 r.values_at(*hash_key_symbols(column)) 308 end 309 else 310 ds.single_value 311 end 312 end
Inserts multiple records into the associated table. This method can be used to efficiently insert a large number of records into a table in a single query if the database supports it. Inserts are automatically wrapped in a transaction.
This method is called with a columns array and an array of value arrays:
DB[:table].import([:x, :y], [[1, 2], [3, 4]]) # INSERT INTO table (x, y) VALUES (1, 2) # INSERT INTO table (x, y) VALUES (3, 4)
This method also accepts a dataset instead of an array of value arrays:
DB[:table].import([:x, :y], DB[:table2].select(:a, :b)) # INSERT INTO table (x, y) SELECT a, b FROM table2
Options:
- :commit_every
-
Open a new transaction for every given number of records. For example, if you provide a value of 50, will commit after every 50 records.
- :return
-
When this is set to :primary_key, returns an array of autoincremented primary key values for the rows inserted. This does not have an effect if
values
is aDataset
. - :server
-
Set the server/shard to use for the transaction and insert queries.
- :slice
-
Same as :commit_every, :commit_every takes precedence.
# File lib/sequel/dataset/actions.rb 340 def import(columns, values, opts=OPTS) 341 return @db.transaction{insert(columns, values)} if values.is_a?(Dataset) 342 343 return if values.empty? 344 raise(Error, 'Using Sequel::Dataset#import with an empty column array is not allowed') if columns.empty? 345 ds = opts[:server] ? server(opts[:server]) : self 346 347 if slice_size = opts.fetch(:commit_every, opts.fetch(:slice, default_import_slice)) 348 offset = 0 349 rows = [] 350 while offset < values.length 351 rows << ds._import(columns, values[offset, slice_size], opts) 352 offset += slice_size 353 end 354 rows.flatten 355 else 356 ds._import(columns, values, opts) 357 end 358 end
Inserts values into the associated table. The returned value is generally the value of the autoincremented primary key for the inserted row, assuming that a single row is inserted and the table has an autoincrementing primary key.
insert
handles a number of different argument formats:
- no arguments or single empty hash
-
Uses
DEFAULT
VALUES - single hash
-
Most common format, treats keys as columns and values as values
- single array
-
Treats entries as values, with no columns
- two arrays
-
Treats first array as columns, second array as values
- single
Dataset
-
Treats as an insert based on a selection from the dataset given, with no columns
- array and dataset
-
Treats as an insert based on a selection from the dataset given, with the columns given by the array.
Examples:
DB[:items].insert # INSERT INTO items DEFAULT VALUES DB[:items].insert({}) # INSERT INTO items DEFAULT VALUES DB[:items].insert([1,2,3]) # INSERT INTO items VALUES (1, 2, 3) DB[:items].insert([:a, :b], [1,2]) # INSERT INTO items (a, b) VALUES (1, 2) DB[:items].insert(a: 1, b: 2) # INSERT INTO items (a, b) VALUES (1, 2) DB[:items].insert(DB[:old_items]) # INSERT INTO items SELECT * FROM old_items DB[:items].insert([:a, :b], DB[:old_items]) # INSERT INTO items (a, b) SELECT * FROM old_items
# File lib/sequel/dataset/actions.rb 396 def insert(*values, &block) 397 sql = insert_sql(*values) 398 if uses_returning?(:insert) 399 returning_fetch_rows(sql, &block) 400 else 401 execute_insert(sql) 402 end 403 end
Reverses the order and then runs first
with the given arguments and block. Note that this will not necessarily give you the last record in the dataset, unless you have an unambiguous order. If there is not currently an order for this dataset, raises an Error
.
DB[:table].order(:id).last # SELECT * FROM table ORDER BY id DESC LIMIT 1 # => {:id=>10} DB[:table].order(Sequel.desc(:id)).last(2) # SELECT * FROM table ORDER BY id ASC LIMIT 2 # => [{:id=>1}, {:id=>2}]
# File lib/sequel/dataset/actions.rb 415 def last(*args, &block) 416 raise(Error, 'No order specified') unless @opts[:order] 417 reverse.first(*args, &block) 418 end
Maps column values for each record in the dataset (if an argument is given) or performs the stock mapping functionality of Enumerable
otherwise. Raises an Error
if both an argument and block are given.
DB[:table].map(:id) # SELECT * FROM table # => [1, 2, 3, ...] DB[:table].map{|r| r[:id] * 2} # SELECT * FROM table # => [2, 4, 6, ...]
You can also provide an array of column names:
DB[:table].map([:id, :name]) # SELECT * FROM table # => [[1, 'A'], [2, 'B'], [3, 'C'], ...]
# File lib/sequel/dataset/actions.rb 434 def map(column=nil, &block) 435 if column 436 raise(Error, 'Must call Dataset#map with either an argument or a block, not both') if block 437 return naked.map(column) if row_proc 438 if column.is_a?(Array) 439 super(){|r| r.values_at(*column)} 440 else 441 super(){|r| r[column]} 442 end 443 else 444 super(&block) 445 end 446 end
Returns the maximum value for the given column/expression. Uses a virtual row block if no argument is given.
DB[:table].max(:id) # SELECT max(id) FROM table LIMIT 1 # => 10 DB[:table].max{function(column)} # SELECT max(function(column)) FROM table LIMIT 1 # => 7
# File lib/sequel/dataset/actions.rb 455 def max(arg=(no_arg = true), &block) 456 arg = Sequel.virtual_row(&block) if no_arg 457 _aggregate(:max, arg) 458 end
Returns the minimum value for the given column/expression. Uses a virtual row block if no argument is given.
DB[:table].min(:id) # SELECT min(id) FROM table LIMIT 1 # => 1 DB[:table].min{function(column)} # SELECT min(function(column)) FROM table LIMIT 1 # => 0
# File lib/sequel/dataset/actions.rb 467 def min(arg=(no_arg = true), &block) 468 arg = Sequel.virtual_row(&block) if no_arg 469 _aggregate(:min, arg) 470 end
This is a front end for import that allows you to submit an array of hashes instead of arrays of columns and values:
DB[:table].multi_insert([{x: 1}, {x: 2}]) # INSERT INTO table (x) VALUES (1) # INSERT INTO table (x) VALUES (2)
Be aware that all hashes should have the same keys if you use this calling method, otherwise some columns could be missed or set to null instead of to default values.
This respects the same options as import
.
# File lib/sequel/dataset/actions.rb 484 def multi_insert(hashes, opts=OPTS) 485 return if hashes.empty? 486 columns = hashes.first.keys 487 import(columns, hashes.map{|h| columns.map{|c| h[c]}}, opts) 488 end
Yields each row in the dataset, but internally uses multiple queries as needed to process the entire result set without keeping all rows in the dataset in memory, even if the underlying driver buffers all query results in memory.
Because this uses multiple queries internally, in order to remain consistent, it also uses a transaction internally. Additionally, to work correctly, the dataset must have unambiguous order. Using an ambiguous order can result in an infinite loop, as well as subtler bugs such as yielding duplicate rows or rows being skipped.
Sequel
checks that the datasets using this method have an order, but it cannot ensure that the order is unambiguous.
Note that this method is not safe to use on many adapters if you are running additional queries inside the provided block. If you are running queries inside the block, use a separate thread or shard inside paged_each
.
Options:
- :rows_per_fetch
-
The number of rows to fetch per query. Defaults to 1000.
- :strategy
-
The strategy to use for paging of results. By default this is :offset, for using an approach with a limit and offset for every page. This can be set to :filter, which uses a limit and a filter that excludes rows from previous pages. In order for this strategy to work, you must be selecting the columns you are ordering by, and none of the columns can contain NULLs. Note that some
Sequel
adapters have optimized implementations that will use cursors or streaming regardless of the :strategy option used. - :filter_values
-
If the strategy: :filter option is used, this option should be a proc that accepts the last retrieved row for the previous page and an array of ORDER BY expressions, and returns an array of values relating to those expressions for the last retrieved row. You will need to use this option if your ORDER BY expressions are not simple columns, if they contain qualified identifiers that would be ambiguous unqualified, if they contain any identifiers that are aliased in SELECT, and potentially other cases.
Examples:
DB[:table].order(:id).paged_each{|row| } # SELECT * FROM table ORDER BY id LIMIT 1000 # SELECT * FROM table ORDER BY id LIMIT 1000 OFFSET 1000 # ... DB[:table].order(:id).paged_each(:rows_per_fetch=>100){|row| } # SELECT * FROM table ORDER BY id LIMIT 100 # SELECT * FROM table ORDER BY id LIMIT 100 OFFSET 100 # ... DB[:table].order(:id).paged_each(strategy: :filter){|row| } # SELECT * FROM table ORDER BY id LIMIT 1000 # SELECT * FROM table WHERE id > 1001 ORDER BY id LIMIT 1000 # ... DB[:table].order(:id).paged_each(strategy: :filter, filter_values: lambda{|row, exprs| [row[:id]]}){|row| } # SELECT * FROM table ORDER BY id LIMIT 1000 # SELECT * FROM table WHERE id > 1001 ORDER BY id LIMIT 1000 # ...
# File lib/sequel/dataset/actions.rb 545 def paged_each(opts=OPTS) 546 unless @opts[:order] 547 raise Sequel::Error, "Dataset#paged_each requires the dataset be ordered" 548 end 549 unless defined?(yield) 550 return enum_for(:paged_each, opts) 551 end 552 553 total_limit = @opts[:limit] 554 offset = @opts[:offset] 555 if server = @opts[:server] 556 opts = Hash[opts] 557 opts[:server] = server 558 end 559 560 rows_per_fetch = opts[:rows_per_fetch] || 1000 561 strategy = if offset || total_limit 562 :offset 563 else 564 opts[:strategy] || :offset 565 end 566 567 db.transaction(opts) do 568 case strategy 569 when :filter 570 filter_values = opts[:filter_values] || proc{|row, exprs| exprs.map{|e| row[hash_key_symbol(e)]}} 571 base_ds = ds = limit(rows_per_fetch) 572 while ds 573 last_row = nil 574 ds.each do |row| 575 last_row = row 576 yield row 577 end 578 ds = (base_ds.where(ignore_values_preceding(last_row, &filter_values)) if last_row) 579 end 580 else 581 offset ||= 0 582 num_rows_yielded = rows_per_fetch 583 total_rows = 0 584 585 while num_rows_yielded == rows_per_fetch && (total_limit.nil? || total_rows < total_limit) 586 if total_limit && total_rows + rows_per_fetch > total_limit 587 rows_per_fetch = total_limit - total_rows 588 end 589 590 num_rows_yielded = 0 591 limit(rows_per_fetch, offset).each do |row| 592 num_rows_yielded += 1 593 total_rows += 1 if total_limit 594 yield row 595 end 596 597 offset += rows_per_fetch 598 end 599 end 600 end 601 602 self 603 end
Returns a hash with key_column values as keys and value_column values as values. Similar to as_hash
, but only selects the columns given. Like as_hash
, it accepts an optional :hash parameter, into which entries will be merged.
DB[:table].select_hash(:id, :name) # SELECT id, name FROM table # => {1=>'a', 2=>'b', ...}
You can also provide an array of column names for either the key_column, the value column, or both:
DB[:table].select_hash([:id, :foo], [:name, :bar]) # SELECT id, foo, name, bar FROM table # => {[1, 3]=>['a', 'c'], [2, 4]=>['b', 'd'], ...}
When using this method, you must be sure that each expression has an alias that Sequel
can determine.
# File lib/sequel/dataset/actions.rb 623 def select_hash(key_column, value_column, opts = OPTS) 624 _select_hash(:as_hash, key_column, value_column, opts) 625 end
Returns a hash with key_column values as keys and an array of value_column values. Similar to to_hash_groups
, but only selects the columns given. Like to_hash_groups
, it accepts an optional :hash parameter, into which entries will be merged.
DB[:table].select_hash_groups(:name, :id) # SELECT id, name FROM table # => {'a'=>[1, 4, ...], 'b'=>[2, ...], ...}
You can also provide an array of column names for either the key_column, the value column, or both:
DB[:table].select_hash_groups([:first, :middle], [:last, :id]) # SELECT first, middle, last, id FROM table # => {['a', 'b']=>[['c', 1], ['d', 2], ...], ...}
When using this method, you must be sure that each expression has an alias that Sequel
can determine.
# File lib/sequel/dataset/actions.rb 644 def select_hash_groups(key_column, value_column, opts = OPTS) 645 _select_hash(:to_hash_groups, key_column, value_column, opts) 646 end
Selects the column given (either as an argument or as a block), and returns an array of all values of that column in the dataset. If you give a block argument that returns an array with multiple entries, the contents of the resulting array are undefined. Raises an Error
if called with both an argument and a block.
DB[:table].select_map(:id) # SELECT id FROM table # => [3, 5, 8, 1, ...] DB[:table].select_map{id * 2} # SELECT (id * 2) FROM table # => [6, 10, 16, 2, ...]
You can also provide an array of column names:
DB[:table].select_map([:id, :name]) # SELECT id, name FROM table # => [[1, 'A'], [2, 'B'], [3, 'C'], ...]
If you provide an array of expressions, you must be sure that each entry in the array has an alias that Sequel
can determine.
# File lib/sequel/dataset/actions.rb 667 def select_map(column=nil, &block) 668 _select_map(column, false, &block) 669 end
The same as select_map
, but in addition orders the array by the column.
DB[:table].select_order_map(:id) # SELECT id FROM table ORDER BY id # => [1, 2, 3, 4, ...] DB[:table].select_order_map{id * 2} # SELECT (id * 2) FROM table ORDER BY (id * 2) # => [2, 4, 6, 8, ...]
You can also provide an array of column names:
DB[:table].select_order_map([:id, :name]) # SELECT id, name FROM table ORDER BY id, name # => [[1, 'A'], [2, 'B'], [3, 'C'], ...]
If you provide an array of expressions, you must be sure that each entry in the array has an alias that Sequel
can determine.
# File lib/sequel/dataset/actions.rb 686 def select_order_map(column=nil, &block) 687 _select_map(column, true, &block) 688 end
Limits the dataset to one record, and returns the first record in the dataset, or nil if the dataset has no records. Users should probably use first
instead of this method. Example:
DB[:test].single_record # SELECT * FROM test LIMIT 1 # => {:column_name=>'value'}
# File lib/sequel/dataset/actions.rb 696 def single_record 697 _single_record_ds.single_record! 698 end
Returns the first record in dataset, without limiting the dataset. Returns nil if the dataset has no records. Users should probably use first
instead of this method. This should only be used if you know the dataset is already limited to a single record. This method may be desirable to use for performance reasons, as it does not clone the receiver. Example:
DB[:test].single_record! # SELECT * FROM test # => {:column_name=>'value'}
# File lib/sequel/dataset/actions.rb 708 def single_record! 709 with_sql_first(select_sql) 710 end
Returns the first value of the first record in the dataset. Returns nil if dataset is empty. Users should generally use get
instead of this method. Example:
DB[:test].single_value # SELECT * FROM test LIMIT 1 # => 'value'
# File lib/sequel/dataset/actions.rb 718 def single_value 719 single_value_ds.each do |r| 720 r.each{|_, v| return v} 721 end 722 nil 723 end
Returns the first value of the first record in the dataset, without limiting the dataset. Returns nil if the dataset is empty. Users should generally use get
instead of this method. Should not be used on graphed datasets or datasets that have row_procs that don’t return hashes. This method may be desirable to use for performance reasons, as it does not clone the receiver.
DB[:test].single_value! # SELECT * FROM test # => 'value'
# File lib/sequel/dataset/actions.rb 733 def single_value! 734 with_sql_single_value(select_sql) 735 end
Returns the sum for the given column/expression. Uses a virtual row block if no column is given.
DB[:table].sum(:id) # SELECT sum(id) FROM table LIMIT 1 # => 55 DB[:table].sum{function(column)} # SELECT sum(function(column)) FROM table LIMIT 1 # => 10
# File lib/sequel/dataset/actions.rb 744 def sum(arg=(no_arg = true), &block) 745 arg = Sequel.virtual_row(&block) if no_arg 746 _aggregate(:sum, arg) 747 end
Alias of as_hash
for backwards compatibility.
# File lib/sequel/dataset/actions.rb 801 def to_hash(*a) 802 as_hash(*a) 803 end
Returns a hash with one column used as key and the values being an array of column values. If the value_column is not given or nil, uses the entire hash as the value.
DB[:table].to_hash_groups(:name, :id) # SELECT * FROM table # {'Jim'=>[1, 4, 16, ...], 'Bob'=>[2], ...} DB[:table].to_hash_groups(:name) # SELECT * FROM table # {'Jim'=>[{:id=>1, :name=>'Jim'}, {:id=>4, :name=>'Jim'}, ...], 'Bob'=>[{:id=>2, :name=>'Bob'}], ...}
You can also provide an array of column names for either the key_column, the value column, or both:
DB[:table].to_hash_groups([:first, :middle], [:last, :id]) # SELECT * FROM table # {['Jim', 'Bob']=>[['Smith', 1], ['Jackson', 4], ...], ...} DB[:table].to_hash_groups([:first, :middle]) # SELECT * FROM table # {['Jim', 'Bob']=>[{:id=>1, :first=>'Jim', :middle=>'Bob', :last=>'Smith'}, ...], ...}
Options:
- :all
-
Use all instead of each to retrieve the objects
- :hash
-
The object into which the values will be placed. If this is not given, an empty hash is used. This can be used to use a hash with a default value or default proc.
# File lib/sequel/dataset/actions.rb 829 def to_hash_groups(key_column, value_column = nil, opts = OPTS) 830 h = opts[:hash] || {} 831 meth = opts[:all] ? :all : :each 832 if value_column 833 return naked.to_hash_groups(key_column, value_column, opts) if row_proc 834 if value_column.is_a?(Array) 835 if key_column.is_a?(Array) 836 public_send(meth){|r| (h[r.values_at(*key_column)] ||= []) << r.values_at(*value_column)} 837 else 838 public_send(meth){|r| (h[r[key_column]] ||= []) << r.values_at(*value_column)} 839 end 840 else 841 if key_column.is_a?(Array) 842 public_send(meth){|r| (h[r.values_at(*key_column)] ||= []) << r[value_column]} 843 else 844 public_send(meth){|r| (h[r[key_column]] ||= []) << r[value_column]} 845 end 846 end 847 elsif key_column.is_a?(Array) 848 public_send(meth){|r| (h[key_column.map{|k| r[k]}] ||= []) << r} 849 else 850 public_send(meth){|r| (h[r[key_column]] ||= []) << r} 851 end 852 h 853 end
Truncates the dataset. Returns nil.
DB[:table].truncate # TRUNCATE table # => nil
# File lib/sequel/dataset/actions.rb 859 def truncate 860 execute_ddl(truncate_sql) 861 end
Updates values for the dataset. The returned value is the number of rows updated. values
should be a hash where the keys are columns to set and values are the values to which to set the columns.
DB[:table].update(x: nil) # UPDATE table SET x = NULL # => 10 DB[:table].update(x: Sequel[:x]+1, y: 0) # UPDATE table SET x = (x + 1), y = 0 # => 10
# File lib/sequel/dataset/actions.rb 872 def update(values=OPTS, &block) 873 sql = update_sql(values) 874 if uses_returning?(:update) 875 returning_fetch_rows(sql, &block) 876 else 877 execute_dui(sql) 878 end 879 end
Return an array of all rows matching the given filter condition, also yielding each row to the given block. Basically the same as where(cond).all(&block), except it can be optimized to not create an intermediate dataset.
DB[:table].where_all(id: [1,2,3]) # SELECT * FROM table WHERE (id IN (1, 2, 3))
# File lib/sequel/dataset/actions.rb 887 def where_all(cond, &block) 888 if loader = _where_loader([cond], nil) 889 loader.all(filter_expr(cond), &block) 890 else 891 where(cond).all(&block) 892 end 893 end
Iterate over all rows matching the given filter condition, yielding each row to the given block. Basically the same as where(cond).each(&block), except it can be optimized to not create an intermediate dataset.
DB[:table].where_each(id: [1,2,3]){|row| p row} # SELECT * FROM table WHERE (id IN (1, 2, 3))
# File lib/sequel/dataset/actions.rb 901 def where_each(cond, &block) 902 if loader = _where_loader([cond], nil) 903 loader.each(filter_expr(cond), &block) 904 else 905 where(cond).each(&block) 906 end 907 end
Filter the datasets using the given filter condition, then return a single value. This assumes that the dataset has already been setup to limit the selection to a single column. Basically the same as where(cond).single_value, except it can be optimized to not create an intermediate dataset.
DB[:table].select(:name).where_single_value(id: 1) # SELECT name FROM table WHERE (id = 1) LIMIT 1
# File lib/sequel/dataset/actions.rb 916 def where_single_value(cond) 917 if loader = cached_where_placeholder_literalizer([cond], nil, :_where_single_value_loader) do |pl| 918 single_value_ds.where(pl.arg) 919 end 920 921 loader.get(filter_expr(cond)) 922 else 923 where(cond).single_value 924 end 925 end
Run the given SQL
and return an array of all rows. If a block is given, each row is yielded to the block after all rows are loaded. See with_sql_each.
# File lib/sequel/dataset/actions.rb 929 def with_sql_all(sql, &block) 930 _all(block){|a| with_sql_each(sql){|r| a << r}} 931 end
Execute the given SQL
and return the number of rows deleted. This exists solely as an optimization, replacing with_sql
(sql).delete. It’s significantly faster as it does not require cloning the current dataset.
# File lib/sequel/dataset/actions.rb 936 def with_sql_delete(sql) 937 execute_dui(sql) 938 end
Run the given SQL
and yield each returned row to the block.
# File lib/sequel/dataset/actions.rb 942 def with_sql_each(sql) 943 if rp = row_proc 944 _with_sql_dataset.fetch_rows(sql){|r| yield rp.call(r)} 945 else 946 _with_sql_dataset.fetch_rows(sql){|r| yield r} 947 end 948 self 949 end
Run the given SQL
and return the first row, or nil if no rows were returned. See with_sql_each.
# File lib/sequel/dataset/actions.rb 953 def with_sql_first(sql) 954 with_sql_each(sql){|r| return r} 955 nil 956 end
Execute the given SQL
and (on most databases) return the primary key of the inserted row.
# File lib/sequel/dataset/actions.rb 969 def with_sql_insert(sql) 970 execute_insert(sql) 971 end
Run the given SQL
and return the first value in the first row, or nil if no rows were returned. For this to make sense, the SQL
given should select only a single value. See with_sql_each.
# File lib/sequel/dataset/actions.rb 961 def with_sql_single_value(sql) 962 if r = with_sql_first(sql) 963 r.each{|_, v| return v} 964 end 965 end
Protected Instance Methods
Internals of import
. If primary key values are requested, use separate insert commands for each row. Otherwise, call multi_insert_sql
and execute each statement it gives separately.
# File lib/sequel/dataset/actions.rb 978 def _import(columns, values, opts) 979 trans_opts = Hash[opts] 980 trans_opts[:server] = @opts[:server] 981 if opts[:return] == :primary_key 982 @db.transaction(trans_opts){values.map{|v| insert(columns, v)}} 983 else 984 stmts = multi_insert_sql(columns, values) 985 @db.transaction(trans_opts){stmts.each{|st| execute_dui(st)}} 986 end 987 end
Return an array of arrays of values given by the symbols in ret_cols.
# File lib/sequel/dataset/actions.rb 990 def _select_map_multiple(ret_cols) 991 map{|r| r.values_at(*ret_cols)} 992 end
Returns an array of the first value in each row.
# File lib/sequel/dataset/actions.rb 995 def _select_map_single 996 k = nil 997 map{|r| r[k||=r.keys.first]} 998 end
A dataset for returning single values from the current dataset.
# File lib/sequel/dataset/actions.rb 1001 def single_value_ds 1002 clone(:limit=>1).ungraphed.naked 1003 end
Private Instance Methods
Cached placeholder literalizer for methods that return values using aggregate functions.
# File lib/sequel/dataset/actions.rb 1017 def _aggregate(function, arg) 1018 if loader = cached_placeholder_literalizer(:"_#{function}_loader") do |pl| 1019 aggregate_dataset.limit(1).select(SQL::Function.new(function, pl.arg).as(function)) 1020 end 1021 loader.get(arg) 1022 else 1023 aggregate_dataset.get(SQL::Function.new(function, arg).as(function)) 1024 end 1025 end
Internals of all and with_sql_all
# File lib/sequel/dataset/actions.rb 1008 def _all(block) 1009 a = [] 1010 yield a 1011 post_load(a) 1012 a.each(&block) if block 1013 a 1014 end
Return a plain symbol given a potentially qualified or aliased symbol, specifying the symbol that is likely to be used as the hash key for the column when records are returned. Return nil if no hash key can be determined
# File lib/sequel/dataset/actions.rb 1116 def _hash_key_symbol(s, recursing=false) 1117 case s 1118 when Symbol 1119 _, c, a = split_symbol(s) 1120 (a || c).to_sym 1121 when SQL::Identifier, SQL::Wrapper 1122 _hash_key_symbol(s.value, true) 1123 when SQL::QualifiedIdentifier 1124 _hash_key_symbol(s.column, true) 1125 when SQL::AliasedExpression 1126 _hash_key_symbol(s.alias, true) 1127 when String 1128 s.to_sym if recursing 1129 end 1130 end
Internals of select_hash
and select_hash_groups
# File lib/sequel/dataset/actions.rb 1028 def _select_hash(meth, key_column, value_column, opts=OPTS) 1029 select(*(key_column.is_a?(Array) ? key_column : [key_column]) + (value_column.is_a?(Array) ? value_column : [value_column])). 1030 public_send(meth, hash_key_symbols(key_column), hash_key_symbols(value_column), opts) 1031 end
Internals of select_map
and select_order_map
# File lib/sequel/dataset/actions.rb 1034 def _select_map(column, order, &block) 1035 ds = ungraphed.naked 1036 columns = Array(column) 1037 virtual_row_columns(columns, block) 1038 select_cols = order ? columns.map{|c| c.is_a?(SQL::OrderedExpression) ? c.expression : c} : columns 1039 ds = ds.order(*columns.map{|c| unaliased_identifier(c)}) if order 1040 if column.is_a?(Array) || (columns.length > 1) 1041 ds.select(*select_cols)._select_map_multiple(hash_key_symbols(select_cols)) 1042 else 1043 ds.select(auto_alias_expression(select_cols.first))._select_map_single 1044 end 1045 end
A cached dataset for a single record for this dataset.
# File lib/sequel/dataset/actions.rb 1048 def _single_record_ds 1049 cached_dataset(:_single_record_ds){clone(:limit=>1)} 1050 end
Loader used for where_all
and where_each.
# File lib/sequel/dataset/actions.rb 1053 def _where_loader(where_args, where_block) 1054 cached_where_placeholder_literalizer(where_args, where_block, :_where_loader) do |pl| 1055 where(pl.arg) 1056 end 1057 end
Cached dataset to use for with_sql_#{all,each,first,single_value}. This is used so that the columns returned by the given SQL
do not affect the receiver of the with_sql_* method.
# File lib/sequel/dataset/actions.rb 1234 def _with_sql_dataset 1235 if @opts[:_with_sql_ds] 1236 self 1237 else 1238 cached_dataset(:_with_sql_ds) do 1239 clone(:_with_sql_ds=>true) 1240 end 1241 end 1242 end
Automatically alias the given expression if it does not have an identifiable alias.
# File lib/sequel/dataset/actions.rb 1060 def auto_alias_expression(v) 1061 case v 1062 when LiteralString, Symbol, SQL::Identifier, SQL::QualifiedIdentifier, SQL::AliasedExpression 1063 v 1064 else 1065 SQL::AliasedExpression.new(v, :v) 1066 end 1067 end
The default number of rows that can be inserted in a single INSERT statement via import. The default is for no limit.
# File lib/sequel/dataset/actions.rb 1071 def default_import_slice 1072 nil 1073 end
Set the server to use to :default unless it is already set in the passed opts
# File lib/sequel/dataset/actions.rb 1076 def default_server_opts(opts) 1077 if @db.sharded? && !opts.has_key?(:server) 1078 opts = Hash[opts] 1079 opts[:server] = @opts[:server] || :default 1080 end 1081 opts 1082 end
Execute the given select SQL
on the database using execute. Use the :read_only server unless a specific server is set.
# File lib/sequel/dataset/actions.rb 1086 def execute(sql, opts=OPTS, &block) 1087 db = @db 1088 if db.sharded? && !opts.has_key?(:server) 1089 opts = Hash[opts] 1090 opts[:server] = @opts[:server] || (@opts[:lock] ? :default : :read_only) 1091 opts 1092 end 1093 db.execute(sql, opts, &block) 1094 end
Execute the given SQL
on the database using execute_ddl.
# File lib/sequel/dataset/actions.rb 1097 def execute_ddl(sql, opts=OPTS, &block) 1098 @db.execute_ddl(sql, default_server_opts(opts), &block) 1099 nil 1100 end
Execute the given SQL
on the database using execute_dui.
# File lib/sequel/dataset/actions.rb 1103 def execute_dui(sql, opts=OPTS, &block) 1104 @db.execute_dui(sql, default_server_opts(opts), &block) 1105 end
Execute the given SQL
on the database using execute_insert.
# File lib/sequel/dataset/actions.rb 1108 def execute_insert(sql, opts=OPTS, &block) 1109 @db.execute_insert(sql, default_server_opts(opts), &block) 1110 end
Return a plain symbol given a potentially qualified or aliased symbol, specifying the symbol that is likely to be used as the hash key for the column when records are returned. Raise Error
if the hash key symbol cannot be returned.
# File lib/sequel/dataset/actions.rb 1136 def hash_key_symbol(s) 1137 if v = _hash_key_symbol(s) 1138 v 1139 else 1140 raise(Error, "#{s.inspect} is not supported, should be a Symbol, SQL::Identifier, SQL::QualifiedIdentifier, or SQL::AliasedExpression") 1141 end 1142 end
If s is an array, return an array with the given hash key symbols. Otherwise, return a hash key symbol for the given expression If a hash key symbol cannot be determined, raise an error.
# File lib/sequel/dataset/actions.rb 1147 def hash_key_symbols(s) 1148 s.is_a?(Array) ? s.map{|c| hash_key_symbol(c)} : hash_key_symbol(s) 1149 end
Returns an expression that will ignore values preceding the given row, using the receiver’s current order. This yields the row and the array of order expressions to the block, which should return an array of values to use.
# File lib/sequel/dataset/actions.rb 1154 def ignore_values_preceding(row) 1155 @opts[:order].map{|v| v.is_a?(SQL::OrderedExpression) ? v.expression : v} 1156 1157 order_exprs = @opts[:order].map do |v| 1158 if v.is_a?(SQL::OrderedExpression) 1159 descending = v.descending 1160 v = v.expression 1161 else 1162 descending = false 1163 end 1164 [v, descending] 1165 end 1166 1167 row_values = yield(row, order_exprs.map(&:first)) 1168 1169 last_expr = [] 1170 cond = order_exprs.zip(row_values).map do |(v, descending), value| 1171 expr = last_expr + [SQL::BooleanExpression.new(descending ? :< : :>, v, value)] 1172 last_expr += [SQL::BooleanExpression.new(:'=', v, value)] 1173 Sequel.&(*expr) 1174 end 1175 Sequel.|(*cond) 1176 end
Downcase identifiers by default when outputing them from the database.
# File lib/sequel/dataset/actions.rb 1179 def output_identifier(v) 1180 v = 'untitled' if v == '' 1181 v.to_s.downcase.to_sym 1182 end
This is run inside .all, after all of the records have been loaded via .each, but before any block passed to all is called. It is called with a single argument, an array of all returned records. Does nothing by default, added to make the model eager loading code simpler.
# File lib/sequel/dataset/actions.rb 1188 def post_load(all_records) 1189 end
Called by insert/update/delete when returning is used. Yields each row as a plain hash to the block if one is given, or returns an array of plain hashes for all rows if a block is not given
# File lib/sequel/dataset/actions.rb 1194 def returning_fetch_rows(sql, &block) 1195 if block 1196 default_server.fetch_rows(sql, &block) 1197 nil 1198 else 1199 rows = [] 1200 default_server.fetch_rows(sql){|r| rows << r} 1201 rows 1202 end 1203 end
Return the unaliased part of the identifier. Handles both implicit aliases in symbols, as well as SQL::AliasedExpression
objects. Other objects are returned as is.
# File lib/sequel/dataset/actions.rb 1208 def unaliased_identifier(c) 1209 case c 1210 when Symbol 1211 table, column, aliaz = split_symbol(c) 1212 if aliaz 1213 table ? SQL::QualifiedIdentifier.new(table, column) : Sequel.identifier(column) 1214 else 1215 c 1216 end 1217 when SQL::AliasedExpression 1218 c.expression 1219 when SQL::OrderedExpression 1220 case expr = c.expression 1221 when Symbol, SQL::AliasedExpression 1222 SQL::OrderedExpression.new(unaliased_identifier(expr), c.descending, :nulls=>c.nulls) 1223 else 1224 c 1225 end 1226 else 1227 c 1228 end 1229 end
3 - User Methods relating to SQL Creation
↑ topPublic Instance Methods
Returns an EXISTS
clause for the dataset as an SQL::PlaceholderLiteralString
.
DB.select(1).where(DB[:items].exists) # SELECT 1 WHERE (EXISTS (SELECT * FROM items))
# File lib/sequel/dataset/sql.rb 14 def exists 15 SQL::PlaceholderLiteralString.new(EXISTS, [self], true) 16 end
Returns an INSERT SQL
query string. See insert
.
DB[:items].insert_sql(a: 1) # => "INSERT INTO items (a) VALUES (1)"
# File lib/sequel/dataset/sql.rb 22 def insert_sql(*values) 23 return static_sql(@opts[:sql]) if @opts[:sql] 24 25 check_insert_allowed! 26 27 columns = [] 28 29 case values.size 30 when 0 31 return insert_sql(OPTS) 32 when 1 33 case vals = values[0] 34 when Hash 35 values = [] 36 vals.each do |k,v| 37 columns << k 38 values << v 39 end 40 when Dataset, Array, LiteralString 41 values = vals 42 end 43 when 2 44 if (v0 = values[0]).is_a?(Array) && ((v1 = values[1]).is_a?(Array) || v1.is_a?(Dataset) || v1.is_a?(LiteralString)) 45 columns, values = v0, v1 46 raise(Error, "Different number of values and columns given to insert_sql") if values.is_a?(Array) and columns.length != values.length 47 end 48 end 49 50 if values.is_a?(Array) && values.empty? && !insert_supports_empty_values? 51 columns, values = insert_empty_columns_values 52 elsif values.is_a?(Dataset) && hoist_cte?(values) && supports_cte?(:insert) 53 ds, values = hoist_cte(values) 54 return ds.clone(:columns=>columns, :values=>values).send(:_insert_sql) 55 end 56 clone(:columns=>columns, :values=>values).send(:_insert_sql) 57 end
Append a literal representation of a value to the given SQL
string.
If an unsupported object is given, an Error
is raised.
# File lib/sequel/dataset/sql.rb 62 def literal_append(sql, v) 63 case v 64 when Symbol 65 if skip_symbol_cache? 66 literal_symbol_append(sql, v) 67 else 68 unless l = db.literal_symbol(v) 69 l = String.new 70 literal_symbol_append(l, v) 71 db.literal_symbol_set(v, l) 72 end 73 sql << l 74 end 75 when String 76 case v 77 when LiteralString 78 sql << v 79 when SQL::Blob 80 literal_blob_append(sql, v) 81 else 82 literal_string_append(sql, v) 83 end 84 when Integer 85 sql << literal_integer(v) 86 when Hash 87 literal_hash_append(sql, v) 88 when SQL::Expression 89 literal_expression_append(sql, v) 90 when Float 91 sql << literal_float(v) 92 when BigDecimal 93 sql << literal_big_decimal(v) 94 when NilClass 95 sql << literal_nil 96 when TrueClass 97 sql << literal_true 98 when FalseClass 99 sql << literal_false 100 when Array 101 literal_array_append(sql, v) 102 when Time 103 v.is_a?(SQLTime) ? literal_sqltime_append(sql, v) : literal_time_append(sql, v) 104 when DateTime 105 literal_datetime_append(sql, v) 106 when Date 107 sql << literal_date(v) 108 when Dataset 109 literal_dataset_append(sql, v) 110 else 111 literal_other_append(sql, v) 112 end 113 end
Returns an array of insert statements for inserting multiple records. This method is used by multi_insert
to format insert statements and expects a keys array and and an array of value arrays.
# File lib/sequel/dataset/sql.rb 118 def multi_insert_sql(columns, values) 119 case multi_insert_sql_strategy 120 when :values 121 sql = LiteralString.new('VALUES ') 122 expression_list_append(sql, values.map{|r| Array(r)}) 123 [insert_sql(columns, sql)] 124 when :union 125 c = false 126 sql = LiteralString.new 127 u = ' UNION ALL SELECT ' 128 f = empty_from_sql 129 values.each do |v| 130 if c 131 sql << u 132 else 133 sql << 'SELECT ' 134 c = true 135 end 136 expression_list_append(sql, v) 137 sql << f if f 138 end 139 [insert_sql(columns, sql)] 140 else 141 values.map{|r| insert_sql(columns, r)} 142 end 143 end
Same as select_sql
, not aliased directly to make subclassing simpler.
# File lib/sequel/dataset/sql.rb 146 def sql 147 select_sql 148 end
Returns a TRUNCATE SQL
query string. See truncate
DB[:items].truncate_sql # => 'TRUNCATE items'
# File lib/sequel/dataset/sql.rb 153 def truncate_sql 154 if opts[:sql] 155 static_sql(opts[:sql]) 156 else 157 check_truncation_allowed! 158 check_not_limited!(:truncate) 159 raise(InvalidOperation, "Can't truncate filtered datasets") if opts[:where] || opts[:having] 160 t = String.new 161 source_list_append(t, opts[:from]) 162 _truncate_sql(t) 163 end 164 end
Formats an UPDATE statement using the given values. See update
.
DB[:items].update_sql(price: 100, category: 'software') # => "UPDATE items SET price = 100, category = 'software'
Raises an Error
if the dataset is grouped or includes more than one table.
# File lib/sequel/dataset/sql.rb 173 def update_sql(values = OPTS) 174 return static_sql(opts[:sql]) if opts[:sql] 175 check_update_allowed! 176 check_not_limited!(:update) 177 178 case values 179 when LiteralString 180 # nothing 181 when String 182 raise Error, "plain string passed to Dataset#update is not supported, use Sequel.lit to use a literal string" 183 end 184 185 clone(:values=>values).send(:_update_sql) 186 end
4 - Methods that describe what the dataset supports
↑ topPublic Instance Methods
Whether this dataset will provide accurate number of rows matched for delete and update statements, true by default. Accurate in this case is the number of rows matched by the dataset’s filter.
# File lib/sequel/dataset/features.rb 19 def provides_accurate_rows_matched? 20 true 21 end
Whether this dataset quotes identifiers.
# File lib/sequel/dataset/features.rb 12 def quote_identifiers? 13 @opts.fetch(:quote_identifiers, true) 14 end
Whether you must use a column alias list for recursive CTEs, false by default.
# File lib/sequel/dataset/features.rb 24 def recursive_cte_requires_column_aliases? 25 false 26 end
Whether type specifiers are required for prepared statement/bound variable argument placeholders (i.e. :bv__integer), false by default.
# File lib/sequel/dataset/features.rb 36 def requires_placeholder_type_specifiers? 37 false 38 end
Whether the dataset requires SQL
standard datetimes. False by default, as most allow strings with ISO 8601 format.
# File lib/sequel/dataset/features.rb 30 def requires_sql_standard_datetimes? 31 false 32 end
Whether the dataset supports common table expressions, false by default. If given, type
can be :select, :insert, :update, or :delete, in which case it determines whether WITH is supported for the respective statement type.
# File lib/sequel/dataset/features.rb 43 def supports_cte?(type=:select) 44 false 45 end
Whether the dataset supports common table expressions in subqueries, false by default. If false, applies the WITH clause to the main query, which can cause issues if multiple WITH clauses use the same name.
# File lib/sequel/dataset/features.rb 50 def supports_cte_in_subqueries? 51 false 52 end
Whether deleting from joined datasets is supported, false by default.
# File lib/sequel/dataset/features.rb 55 def supports_deleting_joins? 56 supports_modifying_joins? 57 end
Whether the database supports derived column lists (e.g. “table_expr AS table_alias(column_alias1, column_alias2, …)”), true by default.
# File lib/sequel/dataset/features.rb 62 def supports_derived_column_lists? 63 true 64 end
Whether the dataset supports or can emulate the DISTINCT ON clause, false by default.
# File lib/sequel/dataset/features.rb 67 def supports_distinct_on? 68 false 69 end
Whether the dataset supports CUBE with GROUP BY, false by default.
# File lib/sequel/dataset/features.rb 72 def supports_group_cube? 73 false 74 end
Whether the dataset supports ROLLUP with GROUP BY, false by default.
# File lib/sequel/dataset/features.rb 77 def supports_group_rollup? 78 false 79 end
Whether the dataset supports GROUPING SETS with GROUP BY, false by default.
# File lib/sequel/dataset/features.rb 82 def supports_grouping_sets? 83 false 84 end
Whether this dataset supports the insert_select
method for returning all columns values directly from an insert query, false by default.
# File lib/sequel/dataset/features.rb 88 def supports_insert_select? 89 supports_returning?(:insert) 90 end
Whether the dataset supports the INTERSECT and EXCEPT compound operations, true by default.
# File lib/sequel/dataset/features.rb 93 def supports_intersect_except? 94 true 95 end
Whether the dataset supports the INTERSECT ALL and EXCEPT ALL compound operations, true by default.
# File lib/sequel/dataset/features.rb 98 def supports_intersect_except_all? 99 true 100 end
Whether the dataset supports the IS TRUE syntax, true by default.
# File lib/sequel/dataset/features.rb 103 def supports_is_true? 104 true 105 end
Whether the dataset supports the JOIN table USING (column1, …) syntax, true by default. If false, support is emulated using JOIN table ON (table.column1 = other_table.column1).
# File lib/sequel/dataset/features.rb 109 def supports_join_using? 110 true 111 end
Whether the dataset supports LATERAL for subqueries in the FROM or JOIN clauses, false by default.
# File lib/sequel/dataset/features.rb 114 def supports_lateral_subqueries? 115 false 116 end
Whether modifying joined datasets is supported, false by default.
# File lib/sequel/dataset/features.rb 129 def supports_modifying_joins? 130 false 131 end
Whether the IN/NOT IN operators support multiple columns when an array of values is given, true by default.
# File lib/sequel/dataset/features.rb 135 def supports_multiple_column_in? 136 true 137 end
Whether the dataset supports skipping raising an error instead of waiting for locked rows when returning data, false by default.
# File lib/sequel/dataset/features.rb 124 def supports_nowait? 125 false 126 end
Whether the dataset supports or can fully emulate the DISTINCT ON clause, including respecting the ORDER BY clause, false by default.
# File lib/sequel/dataset/features.rb 146 def supports_ordered_distinct_on? 147 supports_distinct_on? 148 end
Whether the dataset supports pattern matching by regular expressions, false by default.
# File lib/sequel/dataset/features.rb 151 def supports_regexp? 152 false 153 end
Whether the dataset supports REPLACE syntax, false by default.
# File lib/sequel/dataset/features.rb 156 def supports_replace? 157 false 158 end
Whether the RETURNING clause is supported for the given type of query, false by default. type
can be :insert, :update, or :delete.
# File lib/sequel/dataset/features.rb 162 def supports_returning?(type) 163 false 164 end
Whether the database supports SELECT *, column FROM table
, true by default.
# File lib/sequel/dataset/features.rb 172 def supports_select_all_and_column? 173 true 174 end
Whether the dataset supports skipping locked rows when returning data, false by default.
# File lib/sequel/dataset/features.rb 167 def supports_skip_locked? 168 false 169 end
Whether the dataset supports timezones in literal timestamps, false by default.
# File lib/sequel/dataset/features.rb 177 def supports_timestamp_timezones? 178 false 179 end
Whether the dataset supports fractional seconds in literal timestamps, true by default.
# File lib/sequel/dataset/features.rb 182 def supports_timestamp_usecs? 183 true 184 end
Whether updating joined datasets is supported, false by default.
# File lib/sequel/dataset/features.rb 187 def supports_updating_joins? 188 supports_modifying_joins? 189 end
Whether the dataset supports WHERE TRUE (or WHERE 1 for databases that that use 1 for true), true by default.
# File lib/sequel/dataset/features.rb 216 def supports_where_true? 217 true 218 end
Whether the dataset supports the WINDOW clause to define windows used by multiple window functions, false by default.
# File lib/sequel/dataset/features.rb 193 def supports_window_clause? 194 false 195 end
Whether the dataset supports the given window function option. True by default. This should only be called if supports_window_functions? is true. Possible options are :rows, :range, :groups, :offset, :exclude.
# File lib/sequel/dataset/features.rb 205 def supports_window_function_frame_option?(option) 206 case option 207 when :rows, :range, :offset 208 true 209 else 210 false 211 end 212 end
Whether the dataset supports window functions, false by default.
# File lib/sequel/dataset/features.rb 198 def supports_window_functions? 199 false 200 end
Private Instance Methods
Whether insert(nil) or insert({}) must be emulated by using at least one value.
# File lib/sequel/dataset/features.rb 224 def insert_supports_empty_values? 225 true 226 end
Whether ORDER BY col NULLS FIRST/LAST must be emulated.
# File lib/sequel/dataset/features.rb 234 def requires_emulating_nulls_first? 235 false 236 end
Whether the dataset needs ESCAPE for LIKE for correct behavior.
# File lib/sequel/dataset/features.rb 229 def requires_like_escape? 230 true 231 end
Whether common table expressions are supported in UNION/INTERSECT/EXCEPT clauses.
# File lib/sequel/dataset/features.rb 239 def supports_cte_in_compounds? 240 supports_cte_in_subqueries? 241 end
Whether the dataset supports the FILTER clause for aggregate functions. If not, support is emulated using CASE.
# File lib/sequel/dataset/features.rb 245 def supports_filtered_aggregates? 246 false 247 end
Whether the database supports quoting function names.
# File lib/sequel/dataset/features.rb 250 def supports_quoted_function_names? 251 false 252 end
Whether the RETURNING clause is used for the given dataset. type
can be :insert, :update, or :delete.
# File lib/sequel/dataset/features.rb 256 def uses_returning?(type) 257 opts[:returning] && !@opts[:sql] && supports_returning?(type) 258 end
Whether the dataset uses WITH ROLLUP/CUBE instead of ROLLUP()/CUBE().
# File lib/sequel/dataset/features.rb 261 def uses_with_rollup? 262 false 263 end
6 - Miscellaneous methods
↑ topAttributes
The database related to this dataset. This is the Database
instance that will execute all of this dataset’s queries.
The hash of options for this dataset, keys are symbols.
Public Class Methods
Constructs a new Dataset
instance with an associated database and options. Datasets are usually constructed by invoking the Database#[]
method:
DB[:posts]
Sequel::Dataset
is an abstract class that is not useful by itself. Each database adapter provides a subclass of Sequel::Dataset
, and has the Database#dataset
method return an instance of that subclass.
# File lib/sequel/dataset/misc.rb 25 def initialize(db) 26 @db = db 27 @opts = OPTS 28 @cache = {} 29 freeze 30 end
Public Instance Methods
Define a hash value such that datasets with the same class, DB, and opts will be considered equal.
# File lib/sequel/dataset/misc.rb 34 def ==(o) 35 o.is_a?(self.class) && db == o.db && opts == o.opts 36 end
An object representing the current date or time, should be an instance of Sequel.datetime_class.
# File lib/sequel/dataset/misc.rb 40 def current_datetime 41 Sequel.datetime_class.now 42 end
Return self, as datasets are always frozen.
# File lib/sequel/dataset/misc.rb 50 def dup 51 self 52 end
Yield a dataset for each server in the connection pool that is tied to that server. Intended for use in sharded environments where all servers need to be modified with the same data:
DB[:configs].where(key: 'setting').each_server{|ds| ds.update(value: 'new_value')}
# File lib/sequel/dataset/misc.rb 59 def each_server 60 db.servers.each{|s| yield server(s)} 61 end
Alias for ==
# File lib/sequel/dataset/misc.rb 45 def eql?(o) 46 self == o 47 end
Returns the string with the LIKE metacharacters (% and _) escaped. Useful for when the LIKE term is a user-provided string where metacharacters should not be recognized. Example:
ds.escape_like("foo\\%_") # 'foo\\\%\_'
# File lib/sequel/dataset/misc.rb 68 def escape_like(string) 69 string.gsub(/[\\%_]/){|m| "\\#{m}"} 70 end
Alias of first_source_alias
# File lib/sequel/dataset/misc.rb 91 def first_source 92 first_source_alias 93 end
The first source (primary table) for this dataset. If the dataset doesn’t have a table, raises an Error
. If the table is aliased, returns the aliased name.
DB[:table].first_source_alias # => :table DB[Sequel[:table].as(:t)].first_source_alias # => :t
# File lib/sequel/dataset/misc.rb 103 def first_source_alias 104 source = @opts[:from] 105 if source.nil? || source.empty? 106 raise Error, 'No source specified for query' 107 end 108 case s = source.first 109 when SQL::AliasedExpression 110 s.alias 111 when Symbol 112 _, _, aliaz = split_symbol(s) 113 aliaz ? aliaz.to_sym : s 114 else 115 s 116 end 117 end
The first source (primary table) for this dataset. If the dataset doesn’t have a table, raises an error. If the table is aliased, returns the original table, not the alias
DB[:table].first_source_table # => :table DB[Sequel[:table].as(:t)].first_source_table # => :table
# File lib/sequel/dataset/misc.rb 128 def first_source_table 129 source = @opts[:from] 130 if source.nil? || source.empty? 131 raise Error, 'No source specified for query' 132 end 133 case s = source.first 134 when SQL::AliasedExpression 135 s.expression 136 when Symbol 137 sch, table, aliaz = split_symbol(s) 138 aliaz ? (sch ? SQL::QualifiedIdentifier.new(sch, table) : table.to_sym) : s 139 else 140 s 141 end 142 end
Freeze the opts when freezing the dataset.
# File lib/sequel/dataset/misc.rb 74 def freeze 75 @opts.freeze 76 super 77 end
Define a hash value such that datasets with the same class, DB, and opts, will have the same hash value.
# File lib/sequel/dataset/misc.rb 146 def hash 147 [self.class, db, opts].hash 148 end
Returns a string representation of the dataset including the class name and the corresponding SQL
select statement.
# File lib/sequel/dataset/misc.rb 152 def inspect 153 "#<#{visible_class_name}: #{sql.inspect}>" 154 end
Whether this dataset is a joined dataset (multiple FROM tables or any JOINs).
# File lib/sequel/dataset/misc.rb 157 def joined_dataset? 158 !!((opts[:from].is_a?(Array) && opts[:from].size > 1) || opts[:join]) 159 end
The alias to use for the row_number column, used when emulating OFFSET support and for eager limit strategies
# File lib/sequel/dataset/misc.rb 163 def row_number_column 164 :x_sequel_row_number_x 165 end
Splits a possible implicit alias in c
, handling both SQL::AliasedExpressions and Symbols. Returns an array of two elements, with the first being the main expression, and the second being the alias.
# File lib/sequel/dataset/misc.rb 176 def split_alias(c) 177 case c 178 when Symbol 179 c_table, column, aliaz = split_symbol(c) 180 [c_table ? SQL::QualifiedIdentifier.new(c_table, column.to_sym) : column.to_sym, aliaz] 181 when SQL::AliasedExpression 182 [c.expression, c.alias] 183 when SQL::JoinClause 184 [c.table, c.table_alias] 185 else 186 [c, nil] 187 end 188 end
This returns an SQL::Identifier
or SQL::AliasedExpression
containing an SQL
identifier that represents the unqualified column for the given value. The given value should be a Symbol
, SQL::Identifier
, SQL::QualifiedIdentifier
, or SQL::AliasedExpression
containing one of those. In other cases, this returns nil.
# File lib/sequel/dataset/misc.rb 195 def unqualified_column_for(v) 196 unless v.is_a?(String) 197 _unqualified_column_for(v) 198 end 199 end
Creates a unique table alias that hasn’t already been used in the dataset. table_alias can be any type of object accepted by alias_symbol. The symbol returned will be the implicit alias in the argument, possibly appended with “_N” if the implicit alias has already been used, where N is an integer starting at 0 and increasing until an unused one is found.
You can provide a second addition array argument containing symbols that should not be considered valid table aliases. The current aliases for the FROM and JOIN tables are automatically included in this array.
DB[:table].unused_table_alias(:t) # => :t DB[:table].unused_table_alias(:table) # => :table_0 DB[:table, :table_0].unused_table_alias(:table) # => :table_1 DB[:table, :table_0].unused_table_alias(:table, [:table_1, :table_2]) # => :table_3
# File lib/sequel/dataset/misc.rb 223 def unused_table_alias(table_alias, used_aliases = []) 224 table_alias = alias_symbol(table_alias) 225 used_aliases += opts[:from].map{|t| alias_symbol(t)} if opts[:from] 226 used_aliases += opts[:join].map{|j| j.table_alias ? alias_alias_symbol(j.table_alias) : alias_symbol(j.table)} if opts[:join] 227 if used_aliases.include?(table_alias) 228 i = 0 229 while true 230 ta = :"#{table_alias}_#{i}" 231 return ta unless used_aliases.include?(ta) 232 i += 1 233 end 234 else 235 table_alias 236 end 237 end
Return a modified dataset with quote_identifiers set.
# File lib/sequel/dataset/misc.rb 240 def with_quote_identifiers(v) 241 clone(:quote_identifiers=>v, :skip_symbol_cache=>true) 242 end
Protected Instance Methods
The cached columns for the current dataset.
# File lib/sequel/dataset/misc.rb 271 def _columns 272 cache_get(:_columns) 273 end
Retreive a value from the dataset’s cache in a thread safe manner.
# File lib/sequel/dataset/misc.rb 253 def cache_get(k) 254 Sequel.synchronize{@cache[k]} 255 end
Set a value in the dataset’s cache in a thread safe manner.
# File lib/sequel/dataset/misc.rb 258 def cache_set(k, v) 259 Sequel.synchronize{@cache[k] = v} 260 end
Clear the columns hash for the current dataset. This is not a thread safe operation, so it should only be used if the dataset could not be used by another thread (such as one that was just created via clone).
# File lib/sequel/dataset/misc.rb 266 def clear_columns_cache 267 @cache.delete(:_columns) 268 end
Private Instance Methods
Internal recursive version of unqualified_column_for
, handling Strings inside of other objects.
# File lib/sequel/dataset/misc.rb 345 def _unqualified_column_for(v) 346 case v 347 when Symbol 348 _, c, a = Sequel.split_symbol(v) 349 c = Sequel.identifier(c) 350 a ? c.as(a) : c 351 when String 352 Sequel.identifier(v) 353 when SQL::Identifier 354 v 355 when SQL::QualifiedIdentifier 356 _unqualified_column_for(v.column) 357 when SQL::AliasedExpression 358 if expr = unqualified_column_for(v.expression) 359 SQL::AliasedExpression.new(expr, v.alias) 360 end 361 end 362 end
Check the cache for the given key, returning the value. Otherwise, yield to get the dataset and cache the dataset under the given key.
# File lib/sequel/dataset/misc.rb 279 def cached_dataset(key) 280 unless ds = cache_get(key) 281 ds = yield 282 cache_set(key, ds) 283 end 284 285 ds 286 end
Return a cached placeholder literalizer for the given key if there is one for this dataset. If there isn’t one, increment the counter for the number of calls for the key, and if the counter is at least three, then create a placeholder literalizer by yielding to the block, and cache it.
# File lib/sequel/dataset/misc.rb 293 def cached_placeholder_literalizer(key) 294 if loader = cache_get(key) 295 return loader unless loader.is_a?(Integer) 296 loader += 1 297 298 if loader >= 3 299 loader = Sequel::Dataset::PlaceholderLiteralizer.loader(self){|pl, _| yield pl} 300 cache_set(key, loader) 301 else 302 cache_set(key, loader + 1) 303 loader = nil 304 end 305 elsif cache_sql? 306 cache_set(key, 1) 307 end 308 309 loader 310 end
Return a cached placeholder literalizer for the key, unless where_block is nil and where_args is an empty array or hash. This is designed to guard against placeholder literalizer use when passing arguments to where in the uncached case and filter_expr
if a cached placeholder literalizer is used.
# File lib/sequel/dataset/misc.rb 317 def cached_where_placeholder_literalizer(where_args, where_block, key, &block) 318 where_args = where_args[0] if where_args.length == 1 319 unless where_block 320 return if where_args == OPTS || where_args == EMPTY_ARRAY 321 end 322 323 cached_placeholder_literalizer(key, &block) 324 end
Set the columns for the current dataset.
# File lib/sequel/dataset/misc.rb 327 def columns=(v) 328 cache_set(:_columns, v) 329 end
Set the db, opts, and cache for the copy of the dataset.
# File lib/sequel/dataset/misc.rb 332 def initialize_clone(c, _=nil) 333 @db = c.db 334 @opts = Hash[c.opts] 335 if cols = c.cache_get(:_columns) 336 @cache = {:_columns=>cols} 337 else 338 @cache = {} 339 end 340 end
Return the class name for this dataset, but skip anonymous classes
# File lib/sequel/dataset/misc.rb 365 def visible_class_name 366 c = self.class 367 c = c.superclass while c.name.nil? || c.name == '' 368 c.name 369 end
9 - Internal Methods relating to SQL Creation
↑ topConstants
- BITWISE_METHOD_MAP
- COUNT_FROM_SELF_OPTS
- COUNT_OF_ALL_AS_COUNT
- DEFAULT
- EXISTS
- IS_LITERALS
- IS_OPERATORS
- LIKE_OPERATORS
- N_ARITY_OPERATORS
- QUALIFY_KEYS
- REGEXP_OPERATORS
- TWO_ARITY_OPERATORS
- WILDCARD
Public Class Methods
Given a type (e.g. select) and an array of clauses, return an array of methods to call to build the SQL
string.
# File lib/sequel/dataset/sql.rb 195 def self.clause_methods(type, clauses) 196 clauses.map{|clause| :"#{type}_#{clause}_sql"}.freeze 197 end
Define a dataset literalization method for the given type in the given module, using the given clauses.
Arguments:
- mod
-
Module in which to define method
- type
-
Type of
SQL
literalization method to create, either :select, :insert, :update, or :delete - clauses
-
array of clauses that make up the
SQL
query for the type. This can either be a single array of symbols/strings, or it can be an array of pairs, with the first element in each pair being an if/elsif/else code fragment, and the second element in each pair being an array of symbol/strings for the appropriate branch.
# File lib/sequel/dataset/sql.rb 209 def self.def_sql_method(mod, type, clauses) 210 priv = type == :update || type == :insert 211 cacheable = type == :select || type == :delete 212 213 lines = [] 214 lines << 'private' if priv 215 lines << "def #{'_' if priv}#{type}_sql" 216 lines << 'if sql = opts[:sql]; return static_sql(sql) end' unless priv 217 lines << "if sql = cache_get(:_#{type}_sql); return sql end" if cacheable 218 lines << 'check_delete_allowed!' << 'check_not_limited!(:delete)' if type == :delete 219 lines << 'sql = @opts[:append_sql] || sql_string_origin' 220 221 if clauses.all?{|c| c.is_a?(Array)} 222 clauses.each do |i, cs| 223 lines << i 224 lines.concat(clause_methods(type, cs).map{|x| "#{x}(sql)"}) 225 end 226 lines << 'end' 227 else 228 lines.concat(clause_methods(type, clauses).map{|x| "#{x}(sql)"}) 229 end 230 231 lines << "cache_set(:_#{type}_sql, sql) if cache_sql?" if cacheable 232 lines << 'sql' 233 lines << 'end' 234 235 mod.class_eval lines.join("\n"), __FILE__, __LINE__ 236 end
Public Instance Methods
Append literalization of aliased expression to SQL
string.
# File lib/sequel/dataset/sql.rb 270 def aliased_expression_sql_append(sql, ae) 271 literal_append(sql, ae.expression) 272 as_sql_append(sql, ae.alias, ae.columns) 273 end
Append literalization of array to SQL
string.
# File lib/sequel/dataset/sql.rb 276 def array_sql_append(sql, a) 277 if a.empty? 278 sql << '(NULL)' 279 else 280 sql << '(' 281 expression_list_append(sql, a) 282 sql << ')' 283 end 284 end
Append literalization of boolean constant to SQL
string.
# File lib/sequel/dataset/sql.rb 287 def boolean_constant_sql_append(sql, constant) 288 if (constant == true || constant == false) && !supports_where_true? 289 sql << (constant == true ? '(1 = 1)' : '(1 = 0)') 290 else 291 literal_append(sql, constant) 292 end 293 end
Append literalization of case expression to SQL
string.
# File lib/sequel/dataset/sql.rb 296 def case_expression_sql_append(sql, ce) 297 sql << '(CASE' 298 if ce.expression? 299 sql << ' ' 300 literal_append(sql, ce.expression) 301 end 302 w = " WHEN " 303 t = " THEN " 304 ce.conditions.each do |c,r| 305 sql << w 306 literal_append(sql, c) 307 sql << t 308 literal_append(sql, r) 309 end 310 sql << " ELSE " 311 literal_append(sql, ce.default) 312 sql << " END)" 313 end
Append literalization of cast expression to SQL
string.
# File lib/sequel/dataset/sql.rb 316 def cast_sql_append(sql, expr, type) 317 sql << 'CAST(' 318 literal_append(sql, expr) 319 sql << ' AS ' << db.cast_type_literal(type).to_s 320 sql << ')' 321 end
Append literalization of column all selection to SQL
string.
# File lib/sequel/dataset/sql.rb 324 def column_all_sql_append(sql, ca) 325 qualified_identifier_sql_append(sql, ca.table, WILDCARD) 326 end
Append literalization of complex expression to SQL
string.
# File lib/sequel/dataset/sql.rb 329 def complex_expression_sql_append(sql, op, args) 330 case op 331 when *IS_OPERATORS 332 r = args[1] 333 if r.nil? || supports_is_true? 334 raise(InvalidOperation, 'Invalid argument used for IS operator') unless val = IS_LITERALS[r] 335 sql << '(' 336 literal_append(sql, args[0]) 337 sql << ' ' << op.to_s << ' ' 338 sql << val << ')' 339 elsif op == :IS 340 complex_expression_sql_append(sql, :"=", args) 341 else 342 complex_expression_sql_append(sql, :OR, [SQL::BooleanExpression.new(:"!=", *args), SQL::BooleanExpression.new(:IS, args[0], nil)]) 343 end 344 when :IN, :"NOT IN" 345 cols = args[0] 346 vals = args[1] 347 col_array = true if cols.is_a?(Array) 348 if vals.is_a?(Array) 349 val_array = true 350 empty_val_array = vals == [] 351 end 352 if empty_val_array 353 literal_append(sql, empty_array_value(op, cols)) 354 elsif col_array 355 if !supports_multiple_column_in? 356 if val_array 357 expr = SQL::BooleanExpression.new(:OR, *vals.to_a.map{|vs| SQL::BooleanExpression.from_value_pairs(cols.to_a.zip(vs).map{|c, v| [c, v]})}) 358 literal_append(sql, op == :IN ? expr : ~expr) 359 else 360 old_vals = vals 361 vals = vals.naked if vals.is_a?(Sequel::Dataset) 362 vals = vals.to_a 363 val_cols = old_vals.columns 364 complex_expression_sql_append(sql, op, [cols, vals.map!{|x| x.values_at(*val_cols)}]) 365 end 366 else 367 # If the columns and values are both arrays, use array_sql instead of 368 # literal so that if values is an array of two element arrays, it 369 # will be treated as a value list instead of a condition specifier. 370 sql << '(' 371 literal_append(sql, cols) 372 sql << ' ' << op.to_s << ' ' 373 if val_array 374 array_sql_append(sql, vals) 375 else 376 literal_append(sql, vals) 377 end 378 sql << ')' 379 end 380 else 381 sql << '(' 382 literal_append(sql, cols) 383 sql << ' ' << op.to_s << ' ' 384 literal_append(sql, vals) 385 sql << ')' 386 end 387 when :LIKE, :'NOT LIKE' 388 sql << '(' 389 literal_append(sql, args[0]) 390 sql << ' ' << op.to_s << ' ' 391 literal_append(sql, args[1]) 392 if requires_like_escape? 393 sql << " ESCAPE " 394 literal_append(sql, "\\") 395 end 396 sql << ')' 397 when :ILIKE, :'NOT ILIKE' 398 complex_expression_sql_append(sql, (op == :ILIKE ? :LIKE : :"NOT LIKE"), args.map{|v| Sequel.function(:UPPER, v)}) 399 when :** 400 function_sql_append(sql, Sequel.function(:power, *args)) 401 when *TWO_ARITY_OPERATORS 402 if REGEXP_OPERATORS.include?(op) && !supports_regexp? 403 raise InvalidOperation, "Pattern matching via regular expressions is not supported on #{db.database_type}" 404 end 405 sql << '(' 406 literal_append(sql, args[0]) 407 sql << ' ' << op.to_s << ' ' 408 literal_append(sql, args[1]) 409 sql << ')' 410 when *N_ARITY_OPERATORS 411 sql << '(' 412 c = false 413 op_str = " #{op} " 414 args.each do |a| 415 sql << op_str if c 416 literal_append(sql, a) 417 c ||= true 418 end 419 sql << ')' 420 when :NOT 421 sql << 'NOT ' 422 literal_append(sql, args[0]) 423 when :NOOP 424 literal_append(sql, args[0]) 425 when :'B~' 426 sql << '~' 427 literal_append(sql, args[0]) 428 when :extract 429 sql << 'extract(' << args[0].to_s << ' FROM ' 430 literal_append(sql, args[1]) 431 sql << ')' 432 else 433 raise(InvalidOperation, "invalid operator #{op}") 434 end 435 end
Append literalization of constant to SQL
string.
# File lib/sequel/dataset/sql.rb 438 def constant_sql_append(sql, constant) 439 sql << constant.to_s 440 end
Append literalization of delayed evaluation to SQL
string, causing the delayed evaluation proc to be evaluated.
# File lib/sequel/dataset/sql.rb 444 def delayed_evaluation_sql_append(sql, delay) 445 # Delayed evaluations are used specifically so the SQL 446 # can differ in subsequent calls, so we definitely don't 447 # want to cache the sql in this case. 448 disable_sql_caching! 449 450 if recorder = @opts[:placeholder_literalizer] 451 recorder.use(sql, lambda{delay.call(self)}, nil) 452 else 453 literal_append(sql, delay.call(self)) 454 end 455 end
Append literalization of function call to SQL
string.
# File lib/sequel/dataset/sql.rb 458 def function_sql_append(sql, f) 459 name = f.name 460 opts = f.opts 461 462 if opts[:emulate] 463 if emulate_function?(name) 464 emulate_function_sql_append(sql, f) 465 return 466 end 467 468 name = native_function_name(name) 469 end 470 471 sql << 'LATERAL ' if opts[:lateral] 472 473 case name 474 when SQL::Identifier 475 if supports_quoted_function_names? && opts[:quoted] 476 literal_append(sql, name) 477 else 478 sql << name.value.to_s 479 end 480 when SQL::QualifiedIdentifier 481 if supports_quoted_function_names? && opts[:quoted] != false 482 literal_append(sql, name) 483 else 484 sql << split_qualifiers(name).join('.') 485 end 486 else 487 if supports_quoted_function_names? && opts[:quoted] 488 quote_identifier_append(sql, name) 489 else 490 sql << name.to_s 491 end 492 end 493 494 sql << '(' 495 if filter = opts[:filter] 496 filter = filter_expr(filter, &opts[:filter_block]) 497 end 498 if opts[:*] 499 if filter && !supports_filtered_aggregates? 500 literal_append(sql, Sequel.case({filter=>1}, nil)) 501 filter = nil 502 else 503 sql << '*' 504 end 505 else 506 sql << "DISTINCT " if opts[:distinct] 507 if filter && !supports_filtered_aggregates? 508 expression_list_append(sql, f.args.map{|arg| Sequel.case({filter=>arg}, nil)}) 509 filter = nil 510 else 511 expression_list_append(sql, f.args) 512 end 513 if order = opts[:order] 514 sql << " ORDER BY " 515 expression_list_append(sql, order) 516 end 517 end 518 sql << ')' 519 520 if group = opts[:within_group] 521 sql << " WITHIN GROUP (ORDER BY " 522 expression_list_append(sql, group) 523 sql << ')' 524 end 525 526 if filter 527 sql << " FILTER (WHERE " 528 literal_append(sql, filter) 529 sql << ')' 530 end 531 532 if window = opts[:over] 533 sql << ' OVER ' 534 window_sql_append(sql, window.opts) 535 end 536 537 if opts[:with_ordinality] 538 sql << " WITH ORDINALITY" 539 end 540 end
Append literalization of JOIN clause without ON or USING to SQL
string.
# File lib/sequel/dataset/sql.rb 543 def join_clause_sql_append(sql, jc) 544 table = jc.table 545 table_alias = jc.table_alias 546 table_alias = nil if table == table_alias && !jc.column_aliases 547 sql << ' ' << join_type_sql(jc.join_type) << ' ' 548 identifier_append(sql, table) 549 as_sql_append(sql, table_alias, jc.column_aliases) if table_alias 550 end
Append literalization of JOIN ON clause to SQL
string.
# File lib/sequel/dataset/sql.rb 553 def join_on_clause_sql_append(sql, jc) 554 join_clause_sql_append(sql, jc) 555 sql << ' ON ' 556 literal_append(sql, filter_expr(jc.on)) 557 end
Append literalization of JOIN USING clause to SQL
string.
# File lib/sequel/dataset/sql.rb 560 def join_using_clause_sql_append(sql, jc) 561 join_clause_sql_append(sql, jc) 562 join_using_clause_using_sql_append(sql, jc.using) 563 end
Append literalization of negative boolean constant to SQL
string.
# File lib/sequel/dataset/sql.rb 566 def negative_boolean_constant_sql_append(sql, constant) 567 sql << 'NOT ' 568 boolean_constant_sql_append(sql, constant) 569 end
Append literalization of ordered expression to SQL
string.
# File lib/sequel/dataset/sql.rb 572 def ordered_expression_sql_append(sql, oe) 573 if emulate = requires_emulating_nulls_first? 574 case oe.nulls 575 when :first 576 null_order = 0 577 when :last 578 null_order = 2 579 end 580 581 if null_order 582 literal_append(sql, Sequel.case({{oe.expression=>nil}=>null_order}, 1)) 583 sql << ", " 584 end 585 end 586 587 literal_append(sql, oe.expression) 588 sql << (oe.descending ? ' DESC' : ' ASC') 589 590 unless emulate 591 case oe.nulls 592 when :first 593 sql << " NULLS FIRST" 594 when :last 595 sql << " NULLS LAST" 596 end 597 end 598 end
Append literalization of placeholder literal string to SQL
string.
# File lib/sequel/dataset/sql.rb 601 def placeholder_literal_string_sql_append(sql, pls) 602 args = pls.args 603 str = pls.str 604 sql << '(' if pls.parens 605 if args.is_a?(Hash) 606 if args.empty? 607 sql << str 608 else 609 re = /:(#{args.keys.map{|k| Regexp.escape(k.to_s)}.join('|')})\b/ 610 while true 611 previous, q, str = str.partition(re) 612 sql << previous 613 literal_append(sql, args[($1||q[1..-1].to_s).to_sym]) unless q.empty? 614 break if str.empty? 615 end 616 end 617 elsif str.is_a?(Array) 618 len = args.length 619 str.each_with_index do |s, i| 620 sql << s 621 literal_append(sql, args[i]) unless i == len 622 end 623 unless str.length == args.length || str.length == args.length + 1 624 raise Error, "Mismatched number of placeholders (#{str.length}) and placeholder arguments (#{args.length}) when using placeholder array" 625 end 626 else 627 i = -1 628 match_len = args.length - 1 629 while true 630 previous, q, str = str.partition('?') 631 sql << previous 632 literal_append(sql, args.at(i+=1)) unless q.empty? 633 if str.empty? 634 unless i == match_len 635 raise Error, "Mismatched number of placeholders (#{i+1}) and placeholder arguments (#{args.length}) when using placeholder string" 636 end 637 break 638 end 639 end 640 end 641 sql << ')' if pls.parens 642 end
Append literalization of qualified identifier to SQL
string. If 3 arguments are given, the 2nd should be the table/qualifier and the third should be column/qualified. If 2 arguments are given, the 2nd should be an SQL::QualifiedIdentifier
.
# File lib/sequel/dataset/sql.rb 647 def qualified_identifier_sql_append(sql, table, column=(c = table.column; table = table.table; c)) 648 identifier_append(sql, table) 649 sql << '.' 650 identifier_append(sql, column) 651 end
Append literalization of unqualified identifier to SQL
string. Adds quoting to identifiers (columns and tables). If identifiers are not being quoted, returns name as a string. If identifiers are being quoted quote the name with quoted_identifier.
# File lib/sequel/dataset/sql.rb 657 def quote_identifier_append(sql, name) 658 if name.is_a?(LiteralString) 659 sql << name 660 else 661 name = name.value if name.is_a?(SQL::Identifier) 662 name = input_identifier(name) 663 if quote_identifiers? 664 quoted_identifier_append(sql, name) 665 else 666 sql << name 667 end 668 end 669 end
Append literalization of identifier or unqualified identifier to SQL
string.
# File lib/sequel/dataset/sql.rb 672 def quote_schema_table_append(sql, table) 673 schema, table = schema_and_table(table) 674 if schema 675 quote_identifier_append(sql, schema) 676 sql << '.' 677 end 678 quote_identifier_append(sql, table) 679 end
Append literalization of quoted identifier to SQL
string. This method quotes the given name with the SQL
standard double quote. should be overridden by subclasses to provide quoting not matching the SQL
standard, such as backtick (used by MySQL
and SQLite
).
# File lib/sequel/dataset/sql.rb 685 def quoted_identifier_append(sql, name) 686 sql << '"' << name.to_s.gsub('"', '""') << '"' 687 end
Split the schema information from the table, returning two strings, one for the schema and one for the table. The returned schema may be nil, but the table will always have a string value.
Note that this function does not handle tables with more than one level of qualification (e.g. database.schema.table on Microsoft SQL
Server).
# File lib/sequel/dataset/sql.rb 696 def schema_and_table(table_name, sch=nil) 697 sch = sch.to_s if sch 698 case table_name 699 when Symbol 700 s, t, _ = split_symbol(table_name) 701 [s||sch, t] 702 when SQL::QualifiedIdentifier 703 [table_name.table.to_s, table_name.column.to_s] 704 when SQL::Identifier 705 [sch, table_name.value.to_s] 706 when String 707 [sch, table_name] 708 else 709 raise Error, 'table_name should be a Symbol, SQL::QualifiedIdentifier, SQL::Identifier, or String' 710 end 711 end
Splits table_name into an array of strings.
ds.split_qualifiers(:s) # ['s'] ds.split_qualifiers(Sequel[:t][:s]) # ['t', 's'] ds.split_qualifiers(Sequel[:d][:t][:s]) # ['d', 't', 's'] ds.split_qualifiers(Sequel.qualify(Sequel[:h][:d], Sequel[:t][:s])) # ['h', 'd', 't', 's']
# File lib/sequel/dataset/sql.rb 719 def split_qualifiers(table_name, *args) 720 case table_name 721 when SQL::QualifiedIdentifier 722 split_qualifiers(table_name.table, nil) + split_qualifiers(table_name.column, nil) 723 else 724 sch, table = schema_and_table(table_name, *args) 725 sch ? [sch, table] : [table] 726 end 727 end
Append literalization of subscripts (SQL
array accesses) to SQL
string.
# File lib/sequel/dataset/sql.rb 730 def subscript_sql_append(sql, s) 731 case s.expression 732 when Symbol, SQL::Subscript, SQL::Identifier, SQL::QualifiedIdentifier 733 # nothing 734 else 735 wrap_expression = true 736 sql << '(' 737 end 738 literal_append(sql, s.expression) 739 if wrap_expression 740 sql << ')[' 741 else 742 sql << '[' 743 end 744 sub = s.sub 745 if sub.length == 1 && (range = sub.first).is_a?(Range) 746 literal_append(sql, range.begin) 747 sql << ':' 748 e = range.end 749 e -= 1 if range.exclude_end? && e.is_a?(Integer) 750 literal_append(sql, e) 751 else 752 expression_list_append(sql, s.sub) 753 end 754 sql << ']' 755 end
Append literalization of windows (for window functions) to SQL
string.
# File lib/sequel/dataset/sql.rb 758 def window_sql_append(sql, opts) 759 raise(Error, 'This dataset does not support window functions') unless supports_window_functions? 760 space = false 761 space_s = ' ' 762 763 sql << '(' 764 765 if window = opts[:window] 766 literal_append(sql, window) 767 space = true 768 end 769 770 if part = opts[:partition] 771 sql << space_s if space 772 sql << "PARTITION BY " 773 expression_list_append(sql, Array(part)) 774 space = true 775 end 776 777 if order = opts[:order] 778 sql << space_s if space 779 sql << "ORDER BY " 780 expression_list_append(sql, Array(order)) 781 space = true 782 end 783 784 if frame = opts[:frame] 785 sql << space_s if space 786 787 if frame.is_a?(String) 788 sql << frame 789 else 790 case frame 791 when :all 792 frame_type = :rows 793 frame_start = :preceding 794 frame_end = :following 795 when :rows, :range, :groups 796 frame_type = frame 797 frame_start = :preceding 798 frame_end = :current 799 when Hash 800 frame_type = frame[:type] 801 unless frame_type == :rows || frame_type == :range || frame_type == :groups 802 raise Error, "invalid window :frame :type option: #{frame_type.inspect}" 803 end 804 unless frame_start = frame[:start] 805 raise Error, "invalid window :frame :start option: #{frame_start.inspect}" 806 end 807 frame_end = frame[:end] 808 frame_exclude = frame[:exclude] 809 else 810 raise Error, "invalid window :frame option: #{frame.inspect}" 811 end 812 813 sql << frame_type.to_s.upcase << " " 814 sql << 'BETWEEN ' if frame_end 815 window_frame_boundary_sql_append(sql, frame_start, :preceding) 816 if frame_end 817 sql << " AND " 818 window_frame_boundary_sql_append(sql, frame_end, :following) 819 end 820 821 if frame_exclude 822 sql << " EXCLUDE " 823 824 case frame_exclude 825 when :current 826 sql << "CURRENT ROW" 827 when :group 828 sql << "GROUP" 829 when :ties 830 sql << "TIES" 831 when :no_others 832 sql << "NO OTHERS" 833 else 834 raise Error, "invalid window :frame :exclude option: #{frame_exclude.inspect}" 835 end 836 end 837 end 838 end 839 840 sql << ')' 841 end
Protected Instance Methods
Return a from_self
dataset if an order or limit is specified, so it works as expected with UNION, EXCEPT, and INTERSECT clauses.
# File lib/sequel/dataset/sql.rb 847 def compound_from_self 848 (@opts[:sql] || @opts[:limit] || @opts[:order] || @opts[:offset]) ? from_self : self 849 end
Private Instance Methods
Internals of the check_*_allowed! methods
# File lib/sequel/dataset/sql.rb 945 def _check_modification_allowed!(modifying_joins_supported) 946 raise(InvalidOperation, "Grouped datasets cannot be modified") if opts[:group] 947 raise(InvalidOperation, "Joined datasets cannot be modified") if !modifying_joins_supported && joined_dataset? 948 end
Formats the truncate statement. Assumes the table given has already been literalized.
# File lib/sequel/dataset/sql.rb 855 def _truncate_sql(table) 856 "TRUNCATE TABLE #{table}" 857 end
Clone of this dataset usable in aggregate operations. Does a from_self
if dataset contains any parameters that would affect normal aggregation, or just removes an existing order if not.
# File lib/sequel/dataset/sql.rb 898 def aggregate_dataset 899 options_overlap(COUNT_FROM_SELF_OPTS) ? from_self : unordered 900 end
Returns an appropriate symbol for the alias represented by s.
# File lib/sequel/dataset/sql.rb 860 def alias_alias_symbol(s) 861 case s 862 when Symbol 863 s 864 when String 865 s.to_sym 866 when SQL::Identifier 867 s.value.to_s.to_sym 868 else 869 raise Error, "Invalid alias for alias_alias_symbol: #{s.inspect}" 870 end 871 end
Returns an appropriate alias symbol for the given object, which can be a Symbol
, String
, SQL::Identifier
, SQL::QualifiedIdentifier
, or SQL::AliasedExpression
.
# File lib/sequel/dataset/sql.rb 876 def alias_symbol(sym) 877 case sym 878 when Symbol 879 s, t, a = split_symbol(sym) 880 a || s ? (a || t).to_sym : sym 881 when String 882 sym.to_sym 883 when SQL::Identifier 884 sym.value.to_s.to_sym 885 when SQL::QualifiedIdentifier 886 alias_symbol(sym.column) 887 when SQL::AliasedExpression 888 alias_alias_symbol(sym.alias) 889 else 890 raise Error, "Invalid alias for alias_symbol: #{sym.inspect}" 891 end 892 end
Append aliasing expression to SQL
string.
# File lib/sequel/dataset/sql.rb 903 def as_sql_append(sql, aliaz, column_aliases=nil) 904 sql << ' AS ' 905 quote_identifier_append(sql, aliaz) 906 if column_aliases 907 raise Error, "#{db.database_type} does not support derived column lists" unless supports_derived_column_lists? 908 sql << '(' 909 identifier_list_append(sql, column_aliases) 910 sql << ')' 911 end 912 end
Don’t allow caching SQL
if specifically marked not to.
# File lib/sequel/dataset/sql.rb 915 def cache_sql? 916 !@opts[:no_cache_sql] && !cache_get(:_no_cache_sql) 917 end
Check whether it is allowed to delete from this dataset.
# File lib/sequel/dataset/sql.rb 935 def check_delete_allowed! 936 _check_modification_allowed!(supports_deleting_joins?) 937 end
Check whether it is allowed to insert into this dataset.
# File lib/sequel/dataset/sql.rb 929 def check_insert_allowed! 930 _check_modification_allowed!(false) 931 end
Raise an InvalidOperation exception if modification is not allowed for this dataset. Check whether it is allowed to insert into this dataset. Only for backwards compatibility with older external adapters.
# File lib/sequel/dataset/sql.rb 922 def check_modification_allowed! 923 # SEQUEL6: Remove 924 Sequel::Deprecation.deprecate("Dataset#check_modification_allowed!", "Use check_{insert,delete,update,truncation}_allowed! instead") 925 _check_modification_allowed!(supports_modifying_joins?) 926 end
Raise error if the dataset uses limits or offsets.
# File lib/sequel/dataset/sql.rb 951 def check_not_limited!(type) 952 return if @opts[:skip_limit_check] && type != :truncate 953 raise InvalidOperation, "Dataset##{type} not supported on datasets with limits or offsets" if opts[:limit] || opts[:offset] 954 end
Check whether it is allowed to update this dataset.
# File lib/sequel/dataset/sql.rb 940 def check_update_allowed! 941 _check_modification_allowed!(supports_updating_joins?) 942 end
Append column list to SQL
string. If the column list is empty, a wildcard (*) is appended.
# File lib/sequel/dataset/sql.rb 958 def column_list_append(sql, columns) 959 if (columns.nil? || columns.empty?) 960 sql << '*' 961 else 962 expression_list_append(sql, columns) 963 end 964 end
Yield each pair of arguments to the block, which should return an object representing the SQL
expression for those two arguments. For more than two arguments, the first argument to the block will be result of the previous block call.
# File lib/sequel/dataset/sql.rb 970 def complex_expression_arg_pairs(args) 971 case args.length 972 when 1 973 args[0] 974 when 2 975 yield args[0], args[1] 976 else 977 args.inject{|m, a| yield(m, a)} 978 end 979 end
Append the literalization of the args using complex_expression_arg_pairs
to the given SQL
string, used when database operator/function is 2-ary where Sequel
expression is N-ary.
# File lib/sequel/dataset/sql.rb 984 def complex_expression_arg_pairs_append(sql, args, &block) 985 literal_append(sql, complex_expression_arg_pairs(args, &block)) 986 end
Append literalization of complex expression to SQL
string, for operators unsupported by some databases. Used by adapters for databases that don’t support the operators natively.
# File lib/sequel/dataset/sql.rb 991 def complex_expression_emulate_append(sql, op, args) 992 # :nocov: 993 case op 994 # :nocov: 995 when :% 996 complex_expression_arg_pairs_append(sql, args){|a, b| Sequel.function(:MOD, a, b)} 997 when :>> 998 complex_expression_arg_pairs_append(sql, args){|a, b| Sequel./(a, Sequel.function(:power, 2, b))} 999 when :<< 1000 complex_expression_arg_pairs_append(sql, args){|a, b| Sequel.*(a, Sequel.function(:power, 2, b))} 1001 when :&, :|, :^ 1002 f = BITWISE_METHOD_MAP[op] 1003 complex_expression_arg_pairs_append(sql, args){|a, b| Sequel.function(f, a, b)} 1004 when :'B~' 1005 sql << "((0 - " 1006 literal_append(sql, args[0]) 1007 sql << ") - 1)" 1008 end 1009 end
Append literalization of dataset used in UNION/INTERSECT/EXCEPT clause to SQL
string.
# File lib/sequel/dataset/sql.rb 1012 def compound_dataset_sql_append(sql, ds) 1013 subselect_sql_append(sql, ds) 1014 end
The alias to use for datasets, takes a number to make sure the name is unique.
# File lib/sequel/dataset/sql.rb 1017 def dataset_alias(number) 1018 :"t#{number}" 1019 end
The strftime format to use when literalizing the time.
# File lib/sequel/dataset/sql.rb 1022 def default_timestamp_format 1023 requires_sql_standard_datetimes? ? "TIMESTAMP '%Y-%m-%d %H:%M:%S%N%z'" : "'%Y-%m-%d %H:%M:%S%N%z'" 1024 end
# File lib/sequel/dataset/sql.rb 1026 def delete_delete_sql(sql) 1027 sql << 'DELETE' 1028 end
# File lib/sequel/dataset/sql.rb 1030 def delete_from_sql(sql) 1031 if f = @opts[:from] 1032 sql << ' FROM ' 1033 source_list_append(sql, f) 1034 end 1035 end
Disable caching of SQL
for the current dataset
# File lib/sequel/dataset/sql.rb 1038 def disable_sql_caching! 1039 cache_set(:_no_cache_sql, true) 1040 end
An expression for how to handle an empty array lookup.
# File lib/sequel/dataset/sql.rb 1082 def empty_array_value(op, cols) 1083 {1 => ((op == :IN) ? 0 : 1)} 1084 end
An SQL
FROM clause to use in SELECT statements where the dataset has no from tables.
# File lib/sequel/dataset/sql.rb 1044 def empty_from_sql 1045 nil 1046 end
Whether to emulate the function with the given name. This should only be true if the emulation goes beyond choosing a function with a different name.
# File lib/sequel/dataset/sql.rb 1050 def emulate_function?(name) 1051 false 1052 end
Append literalization of array of expressions to SQL
string, separating them with commas.
# File lib/sequel/dataset/sql.rb 1056 def expression_list_append(sql, columns) 1057 c = false 1058 co = ', ' 1059 columns.each do |col| 1060 sql << co if c 1061 literal_append(sql, col) 1062 c ||= true 1063 end 1064 end
Format the timestamp based on the default_timestamp_format
, with a couple of modifiers. First, allow %N to be used for fractions seconds (if the database supports them), and override %z to always use a numeric offset of hours and minutes.
# File lib/sequel/dataset/sql.rb 1090 def format_timestamp(v) 1091 v2 = db.from_application_timestamp(v) 1092 fmt = default_timestamp_format.gsub(/%[Nz]/) do |m| 1093 if m == '%N' 1094 # Ruby 1.9 supports %N in timestamp formats, but Sequel has supported %N 1095 # for longer in a different way, where the . is already appended and only 6 1096 # decimal places are used by default. 1097 format_timestamp_usec(v.is_a?(DateTime) ? v.sec_fraction*(1000000) : v.usec) if supports_timestamp_usecs? 1098 else 1099 if supports_timestamp_timezones? 1100 # Would like to just use %z format, but it doesn't appear to work on Windows 1101 # Instead, the offset fragment is constructed manually 1102 minutes = (v2.is_a?(DateTime) ? v2.offset * 1440 : v2.utc_offset/60).to_i 1103 format_timestamp_offset(*minutes.divmod(60)) 1104 end 1105 end 1106 end 1107 v2.strftime(fmt) 1108 end
Return the SQL
timestamp fragment to use for the timezone offset.
# File lib/sequel/dataset/sql.rb 1111 def format_timestamp_offset(hour, minute) 1112 sprintf("%+03i%02i", hour, minute) 1113 end
Return the SQL
timestamp fragment to use for the fractional time part. Should start with the decimal point. Uses 6 decimal places by default.
# File lib/sequel/dataset/sql.rb 1117 def format_timestamp_usec(usec, ts=timestamp_precision) 1118 unless ts == 6 1119 usec = usec/(10 ** (6 - ts)) 1120 end 1121 sprintf(".%0#{ts}d", usec) 1122 end
Append literalization of array of grouping elements to SQL
string, seperating them with commas.
# File lib/sequel/dataset/sql.rb 1067 def grouping_element_list_append(sql, columns) 1068 c = false 1069 co = ', ' 1070 columns.each do |col| 1071 sql << co if c 1072 if col.is_a?(Array) && col.empty? 1073 sql << '()' 1074 else 1075 literal_append(sql, Array(col)) 1076 end 1077 c ||= true 1078 end 1079 end
Append literalization of identifier to SQL
string, considering regular strings as SQL
identifiers instead of SQL
strings.
# File lib/sequel/dataset/sql.rb 1126 def identifier_append(sql, v) 1127 if v.is_a?(String) 1128 case v 1129 when LiteralString 1130 sql << v 1131 when SQL::Blob 1132 literal_append(sql, v) 1133 else 1134 quote_identifier_append(sql, v) 1135 end 1136 else 1137 literal_append(sql, v) 1138 end 1139 end
Append literalization of array of identifiers to SQL
string.
# File lib/sequel/dataset/sql.rb 1142 def identifier_list_append(sql, args) 1143 c = false 1144 comma = ', ' 1145 args.each do |a| 1146 sql << comma if c 1147 identifier_append(sql, a) 1148 c ||= true 1149 end 1150 end
Upcase identifiers by default when inputting them into the database.
# File lib/sequel/dataset/sql.rb 1153 def input_identifier(v) 1154 v.to_s.upcase 1155 end
# File lib/sequel/dataset/sql.rb 1166 def insert_columns_sql(sql) 1167 columns = opts[:columns] 1168 if columns && !columns.empty? 1169 sql << ' (' 1170 identifier_list_append(sql, columns) 1171 sql << ')' 1172 end 1173 end
The columns and values to use for an empty insert if the database doesn’t support INSERT with DEFAULT
VALUES.
# File lib/sequel/dataset/sql.rb 1177 def insert_empty_columns_values 1178 [[columns.last], [DEFAULT]] 1179 end
# File lib/sequel/dataset/sql.rb 1181 def insert_insert_sql(sql) 1182 sql << "INSERT" 1183 end
# File lib/sequel/dataset/sql.rb 1157 def insert_into_sql(sql) 1158 sql << " INTO " 1159 if (f = @opts[:from]) && f.length == 1 1160 identifier_append(sql, unaliased_identifier(f.first)) 1161 else 1162 source_list_append(sql, f) 1163 end 1164 end
# File lib/sequel/dataset/sql.rb 1204 def insert_returning_sql(sql) 1205 if opts.has_key?(:returning) 1206 sql << " RETURNING " 1207 column_list_append(sql, Array(opts[:returning])) 1208 end 1209 end
# File lib/sequel/dataset/sql.rb 1185 def insert_values_sql(sql) 1186 case values = opts[:values] 1187 when Array 1188 if values.empty? 1189 sql << " DEFAULT VALUES" 1190 else 1191 sql << " VALUES " 1192 literal_append(sql, values) 1193 end 1194 when Dataset 1195 sql << ' ' 1196 subselect_sql_append(sql, values) 1197 when LiteralString 1198 sql << ' ' << values 1199 else 1200 raise Error, "Unsupported INSERT values type, should be an Array or Dataset: #{values.inspect}" 1201 end 1202 end
SQL
fragment specifying a JOIN type, converts underscores to spaces and upcases.
# File lib/sequel/dataset/sql.rb 1215 def join_type_sql(join_type) 1216 "#{join_type.to_s.gsub('_', ' ').upcase} JOIN" 1217 end
Append USING clause for JOIN USING
# File lib/sequel/dataset/sql.rb 1220 def join_using_clause_using_sql_append(sql, using_columns) 1221 sql << ' USING (' 1222 column_list_append(sql, using_columns) 1223 sql << ')' 1224 end
Append a literalization of the array to SQL
string. Treats as an expression if an array of all two pairs, or as a SQL
array otherwise.
# File lib/sequel/dataset/sql.rb 1228 def literal_array_append(sql, v) 1229 if Sequel.condition_specifier?(v) 1230 literal_expression_append(sql, SQL::BooleanExpression.from_value_pairs(v)) 1231 else 1232 array_sql_append(sql, v) 1233 end 1234 end
SQL
fragment for BigDecimal
# File lib/sequel/dataset/sql.rb 1237 def literal_big_decimal(v) 1238 d = v.to_s("F") 1239 v.nan? || v.infinite? ? "'#{d}'" : d 1240 end
Append literalization of dataset to SQL
string. Does a subselect inside parantheses.
# File lib/sequel/dataset/sql.rb 1248 def literal_dataset_append(sql, v) 1249 sql << 'LATERAL ' if v.opts[:lateral] 1250 sql << '(' 1251 subselect_sql_append(sql, v) 1252 sql << ')' 1253 end
SQL
fragment for Date, using the ISO8601 format.
# File lib/sequel/dataset/sql.rb 1256 def literal_date(v) 1257 if requires_sql_standard_datetimes? 1258 v.strftime("DATE '%Y-%m-%d'") 1259 else 1260 v.strftime("'%Y-%m-%d'") 1261 end 1262 end
SQL
fragment for DateTime
# File lib/sequel/dataset/sql.rb 1265 def literal_datetime(v) 1266 format_timestamp(v) 1267 end
Append literalization of DateTime to SQL
string.
# File lib/sequel/dataset/sql.rb 1270 def literal_datetime_append(sql, v) 1271 sql << literal_datetime(v) 1272 end
Append literalization of SQL::Expression
to SQL
string.
# File lib/sequel/dataset/sql.rb 1275 def literal_expression_append(sql, v) 1276 v.to_s_append(self, sql) 1277 end
SQL
fragment for false
# File lib/sequel/dataset/sql.rb 1280 def literal_false 1281 "'f'" 1282 end
SQL
fragment for Float
# File lib/sequel/dataset/sql.rb 1285 def literal_float(v) 1286 v.to_s 1287 end
SQL
fragment for Integer
# File lib/sequel/dataset/sql.rb 1295 def literal_integer(v) 1296 v.to_s 1297 end
SQL
fragment for nil
# File lib/sequel/dataset/sql.rb 1300 def literal_nil 1301 "NULL" 1302 end
Append a literalization of the object to the given SQL
string. Calls sql_literal_append
if object responds to it, otherwise calls sql_literal
if object responds to it, otherwise raises an error. If a database specific type is allowed, this should be overriden in a subclass.
# File lib/sequel/dataset/sql.rb 1308 def literal_other_append(sql, v) 1309 # We can't be sure if v will always literalize to the same SQL, so 1310 # don't cache SQL for a dataset that uses this. 1311 disable_sql_caching! 1312 1313 if v.respond_to?(:sql_literal_append) 1314 v.sql_literal_append(self, sql) 1315 elsif v.respond_to?(:sql_literal) 1316 sql << v.sql_literal(self) 1317 else 1318 raise Error, "can't express #{v.inspect} as a SQL literal" 1319 end 1320 end
SQL
fragment for Sequel::SQLTime
, containing just the time part
# File lib/sequel/dataset/sql.rb 1323 def literal_sqltime(v) 1324 v.strftime("'%H:%M:%S#{format_timestamp_usec(v.usec, sqltime_precision) if supports_timestamp_usecs?}'") 1325 end
Append literalization of Sequel::SQLTime
to SQL
string.
# File lib/sequel/dataset/sql.rb 1328 def literal_sqltime_append(sql, v) 1329 sql << literal_sqltime(v) 1330 end
Append literalization of string to SQL
string.
# File lib/sequel/dataset/sql.rb 1333 def literal_string_append(sql, v) 1334 sql << "'" << v.gsub("'", "''") << "'" 1335 end
Append literalization of symbol to SQL
string.
# File lib/sequel/dataset/sql.rb 1338 def literal_symbol_append(sql, v) 1339 c_table, column, c_alias = split_symbol(v) 1340 if c_table 1341 quote_identifier_append(sql, c_table) 1342 sql << '.' 1343 end 1344 quote_identifier_append(sql, column) 1345 as_sql_append(sql, c_alias) if c_alias 1346 end
SQL
fragment for Time
# File lib/sequel/dataset/sql.rb 1349 def literal_time(v) 1350 format_timestamp(v) 1351 end
Append literalization of Time to SQL
string.
# File lib/sequel/dataset/sql.rb 1354 def literal_time_append(sql, v) 1355 sql << literal_time(v) 1356 end
SQL
fragment for true
# File lib/sequel/dataset/sql.rb 1359 def literal_true 1360 "'t'" 1361 end
What strategy to use for import/multi_insert. While SQL-92 defaults to allowing multiple rows in a VALUES clause, there are enough databases that don’t allow that that it can’t be the default. Use separate queries by default, which works everywhere.
# File lib/sequel/dataset/sql.rb 1367 def multi_insert_sql_strategy 1368 :separate 1369 end
Get the native function name given the emulated function name.
# File lib/sequel/dataset/sql.rb 1373 def native_function_name(emulated_function) 1374 emulated_function 1375 end
Returns a qualified column name (including a table name) if the column name isn’t already qualified.
# File lib/sequel/dataset/sql.rb 1379 def qualified_column_name(column, table) 1380 if column.is_a?(Symbol) 1381 c_table, column, _ = split_symbol(column) 1382 unless c_table 1383 case table 1384 when Symbol 1385 schema, table, t_alias = split_symbol(table) 1386 t_alias ||= Sequel::SQL::QualifiedIdentifier.new(schema, table) if schema 1387 when Sequel::SQL::AliasedExpression 1388 t_alias = table.alias 1389 end 1390 c_table = t_alias || table 1391 end 1392 ::Sequel::SQL::QualifiedIdentifier.new(c_table, column) 1393 else 1394 column 1395 end 1396 end
Qualify the given expression to the given table.
# File lib/sequel/dataset/sql.rb 1399 def qualified_expression(e, table) 1400 Qualifier.new(table).transform(e) 1401 end
# File lib/sequel/dataset/sql.rb 1403 def select_columns_sql(sql) 1404 sql << ' ' 1405 column_list_append(sql, @opts[:select]) 1406 end
Modify the sql to add a dataset to the via an EXCEPT, INTERSECT, or UNION clause. This uses a subselect for the compound datasets used, because using parantheses doesn’t work on all databases.
# File lib/sequel/dataset/sql.rb 1422 def select_compounds_sql(sql) 1423 return unless c = @opts[:compounds] 1424 c.each do |type, dataset, all| 1425 sql << ' ' << type.to_s.upcase 1426 sql << ' ALL' if all 1427 sql << ' ' 1428 compound_dataset_sql_append(sql, dataset) 1429 end 1430 end
# File lib/sequel/dataset/sql.rb 1408 def select_distinct_sql(sql) 1409 if distinct = @opts[:distinct] 1410 sql << " DISTINCT" 1411 unless distinct.empty? 1412 sql << " ON (" 1413 expression_list_append(sql, distinct) 1414 sql << ')' 1415 end 1416 end 1417 end
# File lib/sequel/dataset/sql.rb 1432 def select_from_sql(sql) 1433 if f = @opts[:from] 1434 sql << ' FROM ' 1435 source_list_append(sql, f) 1436 elsif f = empty_from_sql 1437 sql << f 1438 end 1439 end
# File lib/sequel/dataset/sql.rb 1441 def select_group_sql(sql) 1442 if group = @opts[:group] 1443 sql << " GROUP BY " 1444 if go = @opts[:group_options] 1445 if go == :"grouping sets" 1446 sql << go.to_s.upcase << '(' 1447 grouping_element_list_append(sql, group) 1448 sql << ')' 1449 elsif uses_with_rollup? 1450 expression_list_append(sql, group) 1451 sql << " WITH " << go.to_s.upcase 1452 else 1453 sql << go.to_s.upcase << '(' 1454 expression_list_append(sql, group) 1455 sql << ')' 1456 end 1457 else 1458 expression_list_append(sql, group) 1459 end 1460 end 1461 end
# File lib/sequel/dataset/sql.rb 1463 def select_having_sql(sql) 1464 if having = @opts[:having] 1465 sql << " HAVING " 1466 literal_append(sql, having) 1467 end 1468 end
# File lib/sequel/dataset/sql.rb 1470 def select_join_sql(sql) 1471 if js = @opts[:join] 1472 js.each{|j| literal_append(sql, j)} 1473 end 1474 end
# File lib/sequel/dataset/sql.rb 1476 def select_limit_sql(sql) 1477 if l = @opts[:limit] 1478 sql << " LIMIT " 1479 literal_append(sql, l) 1480 if o = @opts[:offset] 1481 sql << " OFFSET " 1482 literal_append(sql, o) 1483 end 1484 elsif @opts[:offset] 1485 select_only_offset_sql(sql) 1486 end 1487 end
# File lib/sequel/dataset/sql.rb 1489 def select_lock_sql(sql) 1490 case l = @opts[:lock] 1491 when :update 1492 sql << ' FOR UPDATE' 1493 when String 1494 sql << ' ' << l 1495 end 1496 end
Used only if there is an offset and no limit, making it easier to override in the adapter, as many databases do not support just a plain offset with no limit.
# File lib/sequel/dataset/sql.rb 1501 def select_only_offset_sql(sql) 1502 sql << " OFFSET " 1503 literal_append(sql, @opts[:offset]) 1504 end
# File lib/sequel/dataset/sql.rb 1506 def select_order_sql(sql) 1507 if o = @opts[:order] 1508 sql << " ORDER BY " 1509 expression_list_append(sql, o) 1510 end 1511 end
# File lib/sequel/dataset/sql.rb 1515 def select_select_sql(sql) 1516 sql << 'SELECT' 1517 end
# File lib/sequel/dataset/sql.rb 1519 def select_where_sql(sql) 1520 if w = @opts[:where] 1521 sql << " WHERE " 1522 literal_append(sql, w) 1523 end 1524 end
# File lib/sequel/dataset/sql.rb 1528 def select_window_sql(sql) 1529 if ws = @opts[:window] 1530 sql << " WINDOW " 1531 c = false 1532 co = ', ' 1533 as = ' AS ' 1534 ws.map do |name, window| 1535 sql << co if c 1536 literal_append(sql, name) 1537 sql << as 1538 literal_append(sql, window) 1539 c ||= true 1540 end 1541 end 1542 end
# File lib/sequel/dataset/sql.rb 1544 def select_with_sql(sql) 1545 return unless supports_cte? 1546 ctes = opts[:with] 1547 return if !ctes || ctes.empty? 1548 sql << select_with_sql_base 1549 c = false 1550 comma = ', ' 1551 ctes.each do |cte| 1552 sql << comma if c 1553 select_with_sql_cte(sql, cte) 1554 c ||= true 1555 end 1556 sql << ' ' 1557 end
# File lib/sequel/dataset/sql.rb 1562 def select_with_sql_base 1563 "WITH " 1564 end
# File lib/sequel/dataset/sql.rb 1566 def select_with_sql_cte(sql, cte) 1567 select_with_sql_prefix(sql, cte) 1568 literal_dataset_append(sql, cte[:dataset]) 1569 end
# File lib/sequel/dataset/sql.rb 1571 def select_with_sql_prefix(sql, w) 1572 quote_identifier_append(sql, w[:name]) 1573 if args = w[:args] 1574 sql << '(' 1575 identifier_list_append(sql, args) 1576 sql << ')' 1577 end 1578 sql << ' AS ' 1579 1580 case w[:materialized] 1581 when true 1582 sql << "MATERIALIZED " 1583 when false 1584 sql << "NOT MATERIALIZED " 1585 end 1586 end
Whether the symbol cache should be skipped when literalizing the dataset
# File lib/sequel/dataset/sql.rb 1589 def skip_symbol_cache? 1590 @opts[:skip_symbol_cache] 1591 end
Append literalization of array of sources/tables to SQL
string, raising an Error
if there are no sources.
# File lib/sequel/dataset/sql.rb 1595 def source_list_append(sql, sources) 1596 raise(Error, 'No source specified for query') if sources.nil? || sources == [] 1597 identifier_list_append(sql, sources) 1598 end
Delegate to Sequel.split_symbol.
# File lib/sequel/dataset/sql.rb 1601 def split_symbol(sym) 1602 Sequel.split_symbol(sym) 1603 end
The string that is appended to to create the SQL
query, the empty string by default.
# File lib/sequel/dataset/sql.rb 1607 def sql_string_origin 1608 String.new 1609 end
The precision to use for SQLTime
instances (time column values without dates). Defaults to timestamp_precision.
# File lib/sequel/dataset/sql.rb 1613 def sqltime_precision 1614 timestamp_precision 1615 end
SQL
to use if this dataset uses static SQL
. Since static SQL
can be a PlaceholderLiteralString in addition to a String
, we literalize nonstrings. If there is an append_sql for this dataset, append to that SQL
instead of returning the value.
# File lib/sequel/dataset/sql.rb 1621 def static_sql(sql) 1622 if append_sql = @opts[:append_sql] 1623 if sql.is_a?(String) 1624 append_sql << sql 1625 else 1626 literal_append(append_sql, sql) 1627 end 1628 else 1629 if sql.is_a?(String) 1630 sql 1631 else 1632 literal(sql) 1633 end 1634 end 1635 end
Append literalization of the subselect to SQL
string.
# File lib/sequel/dataset/sql.rb 1638 def subselect_sql_append(sql, ds) 1639 sds = subselect_sql_dataset(sql, ds) 1640 sds.sql 1641 unless sds.send(:cache_sql?) 1642 # If subquery dataset does not allow caching SQL, 1643 # then this dataset should not allow caching SQL. 1644 disable_sql_caching! 1645 end 1646 end
# File lib/sequel/dataset/sql.rb 1648 def subselect_sql_dataset(sql, ds) 1649 ds.clone(:append_sql=>sql) 1650 end
The number of decimal digits of precision to use in timestamps.
# File lib/sequel/dataset/sql.rb 1653 def timestamp_precision 1654 supports_timestamp_usecs? ? 6 : 0 1655 end
# File lib/sequel/dataset/sql.rb 1663 def update_set_sql(sql) 1664 sql << ' SET ' 1665 values = @opts[:values] 1666 if values.is_a?(Hash) 1667 update_sql_values_hash(sql, values) 1668 else 1669 sql << values 1670 end 1671 end
# File lib/sequel/dataset/sql.rb 1673 def update_sql_values_hash(sql, values) 1674 c = false 1675 eq = ' = ' 1676 values.each do |k, v| 1677 sql << ', ' if c 1678 if k.is_a?(String) && !k.is_a?(LiteralString) 1679 quote_identifier_append(sql, k) 1680 else 1681 literal_append(sql, k) 1682 end 1683 sql << eq 1684 literal_append(sql, v) 1685 c ||= true 1686 end 1687 end
# File lib/sequel/dataset/sql.rb 1657 def update_table_sql(sql) 1658 sql << ' ' 1659 source_list_append(sql, @opts[:from]) 1660 select_join_sql(sql) if supports_modifying_joins? 1661 end
# File lib/sequel/dataset/sql.rb 1689 def update_update_sql(sql) 1690 sql << 'UPDATE' 1691 end
# File lib/sequel/dataset/sql.rb 1693 def window_frame_boundary_sql_append(sql, boundary, direction) 1694 case boundary 1695 when :current 1696 sql << "CURRENT ROW" 1697 when :preceding 1698 sql << "UNBOUNDED PRECEDING" 1699 when :following 1700 sql << "UNBOUNDED FOLLOWING" 1701 else 1702 if boundary.is_a?(Array) 1703 offset, direction = boundary 1704 unless boundary.length == 2 && (direction == :preceding || direction == :following) 1705 raise Error, "invalid window :frame boundary (:start or :end) option: #{boundary.inspect}" 1706 end 1707 else 1708 offset = boundary 1709 end 1710 1711 case offset 1712 when Numeric, String, SQL::Cast 1713 # nothing 1714 else 1715 raise Error, "invalid window :frame boundary (:start or :end) option: #{boundary.inspect}" 1716 end 1717 1718 literal_append(sql, offset) 1719 sql << (direction == :preceding ? " PRECEDING" : " FOLLOWING") 1720 end 1721 end