Class Sequel::SQL::BooleanExpression
In: lib/sequel_core/sql.rb
Parent: ComplexExpression

Subclass of ComplexExpression where the expression results in a boolean value in SQL.

Methods

Included Modules

BooleanMethods

Public Class methods

Take pairs of values (e.g. a hash or array of arrays of two pairs) and converts it to a BooleanExpression. The operator and args used depends on the case of the right (2nd) argument:

  • 0..10 - left >= 0 AND left <= 10
  • [1,2] - left IN (1,2)
  • nil - left IS NULL
  • /as/ - left ~ ‘as‘
  • :blah - left = blah
  • ‘blah’ - left = ‘blah‘

If multiple arguments are given, they are joined with the op given (AND by default, OR possible). If negate is set to true, all subexpressions are inverted before used. Therefore, the following expressions are equivalent:

  ~from_value_pairs(hash)
  from_value_pairs(hash, :OR, true)

[Source]

     # File lib/sequel_core/sql.rb, line 454
454:       def self.from_value_pairs(pairs, op=:AND, negate=false)
455:         pairs = pairs.collect do |l,r|
456:           ce = case r
457:           when Range
458:             new(:AND, new(:>=, l, r.begin), new(r.exclude_end? ? :< : :<=, l, r.end))
459:           when Array, ::Sequel::Dataset, SQLArray
460:             new(:IN, l, r)
461:           when NilClass
462:             new(:IS, l, r)
463:           when Regexp
464:             StringExpression.like(l, r)
465:           else
466:             new('=''=', l, r)
467:           end
468:           negate ? invert(ce) : ce
469:         end
470:         pairs.length == 1 ? pairs.at(0) : new(op, *pairs)
471:       end

Invert the expression, if possible. If the expression cannot be inverted, raise an error. An inverted expression should match everything that the uninverted expression did not match, and vice-versa.

[Source]

     # File lib/sequel_core/sql.rb, line 476
476:       def self.invert(ce)
477:         case ce
478:         when BooleanExpression
479:           case op = ce.op
480:           when :AND, :OR
481:             BooleanExpression.new(OPERTATOR_INVERSIONS[op], *ce.args.collect{|a| BooleanExpression.invert(a)})
482:           else
483:             BooleanExpression.new(OPERTATOR_INVERSIONS[op], *ce.args.dup)
484:           end
485:         when ComplexExpression
486:           raise(Sequel::Error, "operator #{ce.op} cannot be inverted")
487:         else
488:           BooleanExpression.new(:NOT, ce)
489:         end
490:       end

[Validate]