Class | Sequel::SQL::BooleanExpression
In: | lib/sequel/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/sql.rb, line 423
    423:       def self.from_value_pairs(pairs, op=:AND, negate=false)
    424:         pairs = pairs.collect do |l,r|
    425:           ce = case r
    426:           when Range
    427:             new(:AND, new(:>=, l, r.begin), new(r.exclude_end? ? :< : :<=, l, r.end))
    428:           when Array, ::Sequel::Dataset, SQLArray
    429:             new(:IN, l, r)
    430:           when NilClass, TrueClass, FalseClass
    431:             new(:IS, l, r)
    432:           when Regexp
    433:             StringExpression.like(l, r)
    434:           else
    435:             new('=''=', l, r)
    436:           end
    437:           negate ? invert(ce) : ce
    438:         end
    439:         pairs.length == 1 ? pairs.at(0) : new(op, *pairs)
    440:       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, except for possible issues with SQL NULL (i.e. 1 == NULL is NULL and 1 != NULL is also NULL).

[Source]

         # File lib/sequel/sql.rb, line 446
    446:       def self.invert(ce)
    447:         case ce
    448:         when BooleanExpression
    449:           case op = ce.op
    450:           when :AND, :OR
    451:             BooleanExpression.new(OPERTATOR_INVERSIONS[op], *ce.args.collect{|a| BooleanExpression.invert(a)})
    452:           else
    453:             BooleanExpression.new(OPERTATOR_INVERSIONS[op], *ce.args.dup)
    454:           end
    455:         when ComplexExpression
    456:           raise(Sequel::Error, "operator #{ce.op} cannot be inverted")
    457:         else
    458:           BooleanExpression.new(:NOT, ce)
    459:         end
    460:       end

[Validate]