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 442
    442:       def self.from_value_pairs(pairs, op=:AND, negate=false)
    443:         pairs = pairs.collect do |l,r|
    444:           ce = case r
    445:           when Range
    446:             new(:AND, new(:>=, l, r.begin), new(r.exclude_end? ? :< : :<=, l, r.end))
    447:           when Array, ::Sequel::Dataset, SQLArray
    448:             new(:IN, l, r)
    449:           when NilClass, TrueClass, FalseClass
    450:             new(:IS, l, r)
    451:           when Regexp
    452:             StringExpression.like(l, r)
    453:           else
    454:             new('=''=', l, r)
    455:           end
    456:           negate ? invert(ce) : ce
    457:         end
    458:         pairs.length == 1 ? pairs.at(0) : new(op, *pairs)
    459:       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 465
    465:       def self.invert(ce)
    466:         case ce
    467:         when BooleanExpression
    468:           case op = ce.op
    469:           when :AND, :OR
    470:             BooleanExpression.new(OPERTATOR_INVERSIONS[op], *ce.args.collect{|a| BooleanExpression.invert(a)})
    471:           else
    472:             BooleanExpression.new(OPERTATOR_INVERSIONS[op], *ce.args.dup)
    473:           end
    474:         when StringExpression, NumericExpression
    475:           raise(Sequel::Error, "cannot invert #{ce.inspect}")
    476:         else
    477:           BooleanExpression.new(:NOT, ce)
    478:         end
    479:       end

[Validate]