Module: Sequel::SQL::Builders

Included in:
Sequel
Defined in:
lib/sequel/sql.rb,
lib/sequel/extensions/pg_row.rb,
lib/sequel/extensions/pg_json.rb,
lib/sequel/extensions/pg_array.rb,
lib/sequel/extensions/pg_range.rb,
lib/sequel/extensions/pg_hstore.rb,
lib/sequel/extensions/pg_row_ops.rb,
lib/sequel/extensions/pg_inet_ops.rb,
lib/sequel/extensions/pg_json_ops.rb,
lib/sequel/extensions/pg_array_ops.rb,
lib/sequel/extensions/pg_range_ops.rb,
lib/sequel/extensions/pg_hstore_ops.rb,
lib/sequel/extensions/date_arithmetic.rb

Overview

These methods are designed as replacements for the core extensions, so that Sequel is still easy to use if the core extensions are not enabled.

Instance Method Summary collapse

Instance Method Details

#as(exp, aliaz, columns = nil) ⇒ Object

Create an SQL::AliasedExpression for the given expression and alias.

Sequel.as(:column, :alias) # "column" AS "alias"
Sequel.as(:column, :alias, [:col_alias1, :col_alias2]) # "column" AS "alias"("col_alias1", "col_alias2")



325
326
327
 
# File 'lib/sequel/sql.rb', line 325

def as(exp, aliaz, columns=nil)
  SQL::AliasedExpression.new(exp, aliaz, columns)
end

#asc(arg, opts = OPTS) ⇒ Object

Order the given argument ascending. Options:

:nulls

Set to :first to use NULLS FIRST (so NULL values are ordered before other values), or :last to use NULLS LAST (so NULL values are ordered after other values).

Sequel.asc(:a) # a ASC
Sequel.asc(:b, :nulls=>:last) # b ASC NULLS LAST



338
339
340
 
# File 'lib/sequel/sql.rb', line 338

def asc(arg, opts=OPTS)
  SQL::OrderedExpression.new(arg, false, opts)
end

#blob(s) ⇒ Object

Return an SQL::Blob that holds the same data as this string. Blobs provide proper escaping of binary data. If given a blob, returns it directly.



345
346
347
348
349
350
351
 
# File 'lib/sequel/sql.rb', line 345

def blob(s)
  if s.is_a?(SQL::Blob)
    s
  else
    SQL::Blob.new(s)
  end
end

#case(*args) ⇒ Object

Return an SQL::CaseExpression created with the given arguments.

Sequel.case([[{:a=>[2,3]}, 1]], 0) # SQL: CASE WHEN a IN (2, 3) THEN 1 ELSE 0 END
Sequel.case({:a=>1}, 0, :b) # SQL: CASE b WHEN a THEN 1 ELSE 0 END



357
358
359
 
# File 'lib/sequel/sql.rb', line 357

def case(*args) # core_sql ignore
  SQL::CaseExpression.new(*args)
end

#cast(arg, sql_type) ⇒ Object

Cast the reciever to the given SQL type. You can specify a ruby class as a type, and it is handled similarly to using a database independent type in the schema methods.

Sequel.cast(:a, :integer) # CAST(a AS integer)
Sequel.cast(:a, String) # CAST(a AS varchar(255))



366
367
368
 
# File 'lib/sequel/sql.rb', line 366

def cast(arg, sql_type)
  SQL::Cast.new(arg, sql_type)
end

#cast_numeric(arg, sql_type = nil) ⇒ Object

Cast the reciever to the given SQL type (or the database’s default Integer type if none given), and return the result as a NumericExpression, so you can use the bitwise operators on the result. 

Sequel.cast_numeric(:a) # CAST(a AS integer)
Sequel.cast_numeric(:a, Float) # CAST(a AS double precision)



376
377
378
 
# File 'lib/sequel/sql.rb', line 376

def cast_numeric(arg, sql_type = nil)
  cast(arg, sql_type || Integer).sql_number
end

#cast_string(arg, sql_type = nil) ⇒ Object

Cast the reciever to the given SQL type (or the database’s default String type if none given), and return the result as a StringExpression, so you can use + directly on the result for SQL string concatenation.

Sequel.cast_string(:a) # CAST(a AS varchar(255))
Sequel.cast_string(:a, :text) # CAST(a AS text)



386
387
388
 
# File 'lib/sequel/sql.rb', line 386

def cast_string(arg, sql_type = nil)
  cast(arg, sql_type || String).sql_string
end

#char_length(arg) ⇒ Object

Return an emulated function call for getting the number of characters in the argument:

Sequel.char_length(:a) # char_length(a) -- Most databases
Sequel.char_length(:a) # length(a) -- SQLite



395
396
397
 
# File 'lib/sequel/sql.rb', line 395

def char_length(arg)
  SQL::Function.new!(:char_length, [arg], :emulate=>true)
end

#date_add(expr, interval) ⇒ Object

Return a DateAdd expression, adding an interval to the date/timestamp expr.



32
33
34
 
# File 'lib/sequel/extensions/date_arithmetic.rb', line 32

def date_add(expr, interval)
  DateAdd.new(expr, interval)
end

#date_sub(expr, interval) ⇒ Object

Return a DateAdd expression, adding the negative of the interval to the date/timestamp expr.



38
39
40
41
42
43
44
45
46
47
 
# File 'lib/sequel/extensions/date_arithmetic.rb', line 38

def date_sub(expr, interval)
  interval = if interval.is_a?(Hash)
    h = {}
    interval.each{|k,v| h[k] = -v unless v.nil?}
    h
  else
    -interval
  end
  DateAdd.new(expr, interval)
end

#deep_qualify(qualifier, expr) ⇒ Object

Do a deep qualification of the argument using the qualifier. This recurses into nested structures.

Sequel.deep_qualify(:table, :column) # "table"."column"
Sequel.deep_qualify(:table, Sequel.+(:column, 1)) # "table"."column" + 1
Sequel.deep_qualify(:table, Sequel.like(:a, 'b')) # "table"."a" LIKE 'b' ESCAPE '\'



405
406
407
 
# File 'lib/sequel/sql.rb', line 405

def deep_qualify(qualifier, expr)
  Sequel::Qualifier.new(Sequel, qualifier).transform(expr)
end

#delay(&block) ⇒ Object

Return a delayed evaluation that uses the passed block. This is used to delay evaluations of the code to runtime. For example, with the following code:

ds = DB[:table].where{column > Time.now}

The filter is fixed to the time that where was called. Unless you are only using the dataset once immediately after creating it, that’s probably not desired. If you just want to set it to the time when the query is sent to the database, you can wrap it in Sequel.delay:

ds = DB[:table].where{column > Sequel.delay{Time.now}}

Note that for dates and timestamps, you are probably better off using Sequel::CURRENT_DATE and Sequel::CURRENT_TIMESTAMP instead of this generic delayed evaluation facility.

Raises:



425
426
427
428
 
# File 'lib/sequel/sql.rb', line 425

def delay(&block)
  raise(Error, "Sequel.delay requires a block") unless block
  SQL::DelayedEvaluation.new(block)
end

#desc(arg, opts = OPTS) ⇒ Object

Order the given argument descending. Options:

:nulls

Set to :first to use NULLS FIRST (so NULL values are ordered before other values), or :last to use NULLS LAST (so NULL values are ordered after other values).

Sequel.desc(:a) # b DESC
Sequel.desc(:b, :nulls=>:first) # b DESC NULLS FIRST



439
440
441
 
# File 'lib/sequel/sql.rb', line 439

def desc(arg, opts=OPTS)
  SQL::OrderedExpression.new(arg, true, opts)
end

#expr(arg = (no_arg=true), &block) ⇒ Object

Wraps the given object in an appropriate Sequel wrapper. If the given object is already a Sequel object, return it directly. For condition specifiers (hashes and arrays of two pairs), true, and false, return a boolean expressions. For numeric objects, return a numeric expression. For strings, return a string expression. For procs or when the method is passed a block, evaluate it as a virtual row and wrap it appropriately. In all other cases, use a generic wrapper.

This method allows you to construct SQL expressions that are difficult to construct via other methods. For example:

Sequel.expr(1) - :a # SQL: (1 - a)



455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
 
# File 'lib/sequel/sql.rb', line 455

def expr(arg=(no_arg=true), &block)
  if block_given?
    if no_arg
      return expr(block)
    else
      raise Error, 'cannot provide both an argument and a block to Sequel.expr'
    end
  elsif no_arg
    raise Error, 'must provide either an argument or a block to Sequel.expr'
  end

  case arg
  when Symbol
    t, c, a = Sequel.split_symbol(arg)

    arg = if t
      SQL::QualifiedIdentifier.new(t, c)
    else
      SQL::Identifier.new(c)
    end

    if a
      arg = SQL::AliasedExpression.new(arg, a)
    end

    arg
  when SQL::Expression, LiteralString, SQL::Blob
    arg
  when Hash
    SQL::BooleanExpression.from_value_pairs(arg, :AND)
  when Array
    if condition_specifier?(arg)
      SQL::BooleanExpression.from_value_pairs(arg, :AND)
    else
      SQL::Wrapper.new(arg)
    end
  when Numeric
    SQL::NumericExpression.new(:NOOP, arg)
  when String
    SQL::StringExpression.new(:NOOP, arg)
  when TrueClass, FalseClass
    SQL::BooleanExpression.new(:NOOP, arg)
  when Proc
    expr(virtual_row(&arg))
  else
    SQL::Wrapper.new(arg)
  end
end

#extract(datetime_part, exp) ⇒ Object

Extract a datetime_part (e.g. year, month) from the given expression:

Sequel.extract(:year, :date) # extract(year FROM "date")



508
509
510
 
# File 'lib/sequel/sql.rb', line 508

def extract(datetime_part, exp)
  SQL::NumericExpression.new(:extract, datetime_part, exp)
end

#function(name, *args) ⇒ Object

Returns a Sequel::SQL::Function with the function name and the given arguments.

Sequel.function(:now) # SQL: now()
Sequel.function(:substr, :a, 1) # SQL: substr(a, 1)



517
518
519
 
# File 'lib/sequel/sql.rb', line 517

def function(name, *args)
  SQL::Function.new(name, *args)
end

#hstore(v) ⇒ Object

Return a Postgres::HStore proxy for the given hash.



317
318
319
320
321
322
323
324
325
326
327
 
# File 'lib/sequel/extensions/pg_hstore.rb', line 317

def hstore(v)
  case v
  when Postgres::HStore
    v
  when Hash
    Postgres::HStore.new(v)
  else
    # May not be defined unless the pg_hstore_ops extension is used
    hstore_op(v)
  end
end

#hstore_op(v) ⇒ Object

Return the object wrapped in an Postgres::HStoreOp.



324
325
326
327
328
329
330
331
 
# File 'lib/sequel/extensions/pg_hstore_ops.rb', line 324

def hstore_op(v)
  case v
  when Postgres::HStoreOp
    v
  else
    Postgres::HStoreOp.new(v)
  end
end

#identifier(name) ⇒ Object

Return the argument wrapped as an SQL::Identifier.

Sequel.identifier(:a__b) # "a__b"



524
525
526
 
# File 'lib/sequel/sql.rb', line 524

def identifier(name)
  SQL::Identifier.new(name)
end

#ilike(*args) ⇒ Object

Create a BooleanExpression case insensitive (if the database supports it) pattern match of the receiver with the given patterns. See SQL::StringExpression.like.

Sequel.ilike(:a, 'A%') # "a" ILIKE 'A%' ESCAPE '\'



561
562
563
 
# File 'lib/sequel/sql.rb', line 561

def ilike(*args)
  SQL::StringExpression.like(*(args << {:case_insensitive=>true}))
end

#join(args, joiner = nil) ⇒ Object

Return a Sequel::SQL::StringExpression representing an SQL string made up of the concatenation of the given array’s elements. If an argument is passed, it is used in between each element of the array in the SQL concatenation.

Sequel.join([:a]) # SQL: a
Sequel.join([:a, :b]) # SQL: a || b
Sequel.join([:a, 'b']) # SQL: a || 'b'
Sequel.join(['a', :b], ' ') # SQL: 'a' || ' ' || b

Raises:



537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
 
# File 'lib/sequel/sql.rb', line 537

def join(args, joiner=nil)
  raise Error, 'argument to Sequel.join must be an array' unless args.is_a?(Array)
  if joiner
    args = args.zip([joiner]*args.length).flatten
    args.pop
  end

  return SQL::StringExpression.new(:NOOP, '') if args.empty?

  args = args.map do |a|
    case a
    when Symbol, ::Sequel::SQL::Expression, ::Sequel::LiteralString, TrueClass, FalseClass, NilClass
      a
    else
      a.to_s
    end
  end
  SQL::StringExpression.new(:'||', *args)
end

#like(*args) ⇒ Object

Create a SQL::BooleanExpression case sensitive (if the database supports it) pattern match of the receiver with the given patterns. See SQL::StringExpression.like.

Sequel.like(:a, 'A%') # "a" LIKE 'A%' ESCAPE '\'



569
570
571
 
# File 'lib/sequel/sql.rb', line 569

def like(*args)
  SQL::StringExpression.like(*args)
end

#lit(s, *args) ⇒ Object

Converts a string into a Sequel::LiteralString, in order to override string literalization, e.g.:

DB[:items].filter(:abc => 'def').sql #=>
  "SELECT * FROM items WHERE (abc = 'def')"

DB[:items].filter(:abc => Sequel.lit('def')).sql #=>
  "SELECT * FROM items WHERE (abc = def)"

You can also provide arguments, to create a Sequel::SQL::PlaceholderLiteralString:

DB[:items].select{|o| o.count(Sequel.lit('DISTINCT ?', :a))}.sql #=>
  "SELECT count(DISTINCT a) FROM items"



586
587
588
589
590
591
592
593
594
595
596
 
# File 'lib/sequel/sql.rb', line 586

def lit(s, *args) # core_sql ignore
  if args.empty?
    if s.is_a?(LiteralString)
      s
    else
      LiteralString.new(s)
    end
  else
    SQL::PlaceholderLiteralString.new(s, args) 
  end
end

#negate(arg) ⇒ Object

Return a Sequel::SQL::BooleanExpression created from the condition specifier, matching none of the conditions.

Sequel.negate(:a=>true) # SQL: a IS NOT TRUE
Sequel.negate([[:a, true]]) # SQL: a IS NOT TRUE
Sequel.negate([[:a, 1], [:b, 2]]) # SQL: ((a != 1) AND (b != 2))



604
605
606
607
608
609
610
 
# File 'lib/sequel/sql.rb', line 604

def negate(arg)
  if condition_specifier?(arg)
    SQL::BooleanExpression.from_value_pairs(arg, :AND, true)
  else
    raise Error, 'must pass a conditions specifier to Sequel.negate'
  end
end

#or(arg) ⇒ Object

Return a Sequel::SQL::BooleanExpression created from the condition specifier, matching any of the conditions.

Sequel.or(:a=>true) # SQL: a IS TRUE
Sequel.or([[:a, true]]) # SQL: a IS TRUE
Sequel.or([[:a, 1], [:b, 2]]) # SQL: ((a = 1) OR (b = 2))



618
619
620
621
622
623
624
 
# File 'lib/sequel/sql.rb', line 618

def or(arg)
  if condition_specifier?(arg)
    SQL::BooleanExpression.from_value_pairs(arg, :OR, false)
  else
    raise Error, 'must pass a conditions specifier to Sequel.or'
  end
end

#pg_array(v, array_type = nil) ⇒ Object

Return a Postgres::PGArray proxy for the given array and database array type.



573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
 
# File 'lib/sequel/extensions/pg_array.rb', line 573

def pg_array(v, array_type=nil)
  case v
  when Postgres::PGArray
    if array_type.nil? || v.array_type == array_type
      v
    else
      Postgres::PGArray.new(v.to_a, array_type)
    end
  when Array
    Postgres::PGArray.new(v, array_type)
  else
    # May not be defined unless the pg_array_ops extension is used
    pg_array_op(v)
  end
end

#pg_array_op(v) ⇒ Object

Return the object wrapped in an Postgres::ArrayOp.



291
292
293
294
295
296
297
298
 
# File 'lib/sequel/extensions/pg_array_ops.rb', line 291

def pg_array_op(v)
  case v
  when Postgres::ArrayOp
    v
  else
    Postgres::ArrayOp.new(v)
  end
end

#pg_inet_op(v) ⇒ Object

Return the expression wrapped in the Postgres::InetOp.



167
168
169
170
171
172
173
174
 
# File 'lib/sequel/extensions/pg_inet_ops.rb', line 167

def pg_inet_op(v)
  case v
  when Postgres::InetOp
    v
  else
    Postgres::InetOp.new(v)
  end
end

#pg_json(v) ⇒ Object

Wrap the array or hash in a Postgres::JSONArray or Postgres::JSONHash.



268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
 
# File 'lib/sequel/extensions/pg_json.rb', line 268

def pg_json(v)
  case v
  when Postgres::JSONArray, Postgres::JSONHash
    v
  when Array
    Postgres::JSONArray.new(v)
  when Hash
    Postgres::JSONHash.new(v)
  when Postgres::JSONBArray
    Postgres::JSONArray.new(v.to_a)
  when Postgres::JSONBHash
    Postgres::JSONHash.new(v.to_hash)
  else
    Sequel.pg_json_op(v)
  end
end

#pg_json_op(v) ⇒ Object

Return the object wrapped in an Postgres::JSONOp.



399
400
401
402
403
404
405
406
 
# File 'lib/sequel/extensions/pg_json_ops.rb', line 399

def pg_json_op(v)
  case v
  when Postgres::JSONOp
    v
  else
    Postgres::JSONOp.new(v)
  end
end

#pg_jsonb(v) ⇒ Object

Wrap the array or hash in a Postgres::JSONBArray or Postgres::JSONBHash.



286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
 
# File 'lib/sequel/extensions/pg_json.rb', line 286

def pg_jsonb(v)
  case v
  when Postgres::JSONBArray, Postgres::JSONBHash
    v
  when Array
    Postgres::JSONBArray.new(v)
  when Hash
    Postgres::JSONBHash.new(v)
  when Postgres::JSONArray
    Postgres::JSONBArray.new(v.to_a)
  when Postgres::JSONHash
    Postgres::JSONBHash.new(v.to_hash)
  else
    Sequel.pg_jsonb_op(v)
  end
end

#pg_jsonb_op(v) ⇒ Object

Return the object wrapped in an Postgres::JSONBOp.



409
410
411
412
413
414
415
416
 
# File 'lib/sequel/extensions/pg_json_ops.rb', line 409

def pg_jsonb_op(v)
  case v
  when Postgres::JSONBOp
    v
  else
    Postgres::JSONBOp.new(v)
  end
end

#pg_range(v, db_type = nil) ⇒ Object

Convert the object to a Postgres::PGRange.



517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
 
# File 'lib/sequel/extensions/pg_range.rb', line 517

def pg_range(v, db_type=nil)
  case v
  when Postgres::PGRange
    if db_type.nil? || v.db_type == db_type
      v
    else
      Postgres::PGRange.new(v.begin, v.end, :exclude_begin=>v.exclude_begin?, :exclude_end=>v.exclude_end?, :db_type=>db_type)
    end
  when Range
    Postgres::PGRange.from_range(v, db_type)
  else
    # May not be defined unless the pg_range_ops extension is used
    pg_range_op(v)
  end
end

#pg_range_op(v) ⇒ Object

Return the expression wrapped in the Postgres::RangeOp.



129
130
131
132
133
134
135
136
 
# File 'lib/sequel/extensions/pg_range_ops.rb', line 129

def pg_range_op(v)
  case v
  when Postgres::RangeOp
    v
  else
    Postgres::RangeOp.new(v)
  end
end

#pg_row(expr) ⇒ Object

Wraps the expr array in an anonymous Postgres::PGRow::ArrayRow instance.



582
583
584
585
586
587
588
589
590
 
# File 'lib/sequel/extensions/pg_row.rb', line 582

def pg_row(expr)
  case expr
  when Array
    Postgres::PGRow::ArrayRow.new(expr)
  else
    # Will only work if pg_row_ops extension is loaded
    pg_row_op(expr)
  end
end

#pg_row_op(expr) ⇒ Object

Return a PGRowOp wrapping the given expression.



166
167
168
 
# File 'lib/sequel/extensions/pg_row_ops.rb', line 166

def pg_row_op(expr)
  Postgres::PGRowOp.wrap(expr)
end

#qualify(qualifier, identifier) ⇒ Object

Create a qualified identifier with the given qualifier and identifier

Sequel.qualify(:table, :column) # "table"."column"
Sequel.qualify(:schema, :table) # "schema"."table"
Sequel.qualify(:table, :column).qualify(:schema) # "schema"."table"."column"



631
632
633
 
# File 'lib/sequel/sql.rb', line 631

def qualify(qualifier, identifier)
  SQL::QualifiedIdentifier.new(qualifier, identifier)
end

#subscript(exp, *subs) ⇒ Object

Return an SQL::Subscript with the given arguments, representing an SQL array access.

Sequel.subscript(:array, 1) # array[1]
Sequel.subscript(:array, 1, 2) # array[1, 2]
Sequel.subscript(:array, [1, 2]) # array[1, 2]
Sequel.subscript(:array, 1..2) # array[1:2]
Sequel.subscript(:array, 1...3) # array[1:2]



643
644
645
 
# File 'lib/sequel/sql.rb', line 643

def subscript(exp, *subs)
  SQL::Subscript.new(exp, subs.flatten)
end

#trim(arg) ⇒ Object

Return an emulated function call for trimming a string of spaces from both sides (similar to ruby’s String#strip).

Sequel.trim(:a) # trim(a) -- Most databases
Sequel.trim(:a) # ltrim(rtrim(a)) -- Microsoft SQL Server



652
653
654
 
# File 'lib/sequel/sql.rb', line 652

def trim(arg)
  SQL::Function.new!(:trim, [arg], :emulate=>true)
end

#value_list(arg) ⇒ Object

Return a SQL::ValueList created from the given array. Used if the array contains all two element arrays and you want it treated as an SQL value list (IN predicate) instead of as a conditions specifier (similar to a hash). This is not necessary if you are using this array as a value in a filter, but may be necessary if you are using it as a value with placeholder SQL:

DB[:a].filter([:a, :b]=>[[1, 2], [3, 4]]) # SQL: (a, b) IN ((1, 2), (3, 4))
DB[:a].filter('(a, b) IN ?', [[1, 2], [3, 4]]) # SQL: (a, b) IN ((1 = 2) AND (3 = 4))
DB[:a].filter('(a, b) IN ?', Sequel.value_list([[1, 2], [3, 4]])) # SQL: (a, b) IN ((1, 2), (3, 4))

Raises:



665
666
667
668
 
# File 'lib/sequel/sql.rb', line 665

def value_list(arg)
  raise Error, 'argument to Sequel.value_list must be an array' unless arg.is_a?(Array)
  SQL::ValueList.new(arg)
end