Class: Sequel::SQL::BooleanExpression

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

from_value_pairs invert

### Included Modules

BooleanMethods

### Public Class methods

from_value_pairs(pairs, op=:AND, negate=false)

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(ce)

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]