Class | Array
In: | lib/sequel/core_sql.rb
Parent: | Object

Sequel extends `Array` to add methods to implement the SQL DSL. Most of these methods require that the array not be empty and that it must consist solely of other arrays that have exactly two elements.

### Methods

all_two_pairs? case sql_array sql_expr sql_negate sql_or sql_string_join sql_value_list ~

### Public Instance methods

all_two_pairs?()

`true` if the array is not empty and all of its elements are arrays of size 2, `false` otherwise. This is used to determine if the array could be a specifier of conditions, used similarly to a hash but allowing for duplicate keys and a specific order.

       [].to_a.all_two_pairs? # => false
       [:a].to_a.all_two_pairs? # => false
       [[:b]].to_a.all_two_pairs? # => false
       [[:a, 1]].to_a.all_two_pairs? # => true

[Source]

        # File lib/sequel/core_sql.rb, line 23
    23:   def all_two_pairs?
    24:     !empty? && all?{|i| (Array === i) && (i.length == 2)}
    25:   end

case(*args)

Return a `Sequel::SQL::CaseExpression` with this array as the conditions and the given default value and expression.

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

[Source]

        # File lib/sequel/core_sql.rb, line 32
    32:   def case(*args)
    33:     ::Sequel::SQL::CaseExpression.new(self, *args)
    34:   end

sql_array()

Alias for sql_value_list

sql_expr()

Return a `Sequel::SQL::BooleanExpression` created from this array, matching all of the conditions. Rarely do you need to call this explicitly, as Sequel generally assumes that arrays of two element arrays specify this type of condition. One case where it can be necessary to use this is if you are using the object as a value in a filter hash and want to use the = operator instead of the IN operator (which is used by default for arrays of two element arrays).

      [[:a, true]].sql_expr # SQL: a IS TRUE
      [[:a, 1], [:b, [2, 3]]].sql_expr # SQL: a = 1 AND b IN (2, 3)

[Source]

        # File lib/sequel/core_sql.rb, line 61
    61:   def sql_expr
    62:     sql_expr_if_all_two_pairs
    63:   end

sql_negate()

Return a `Sequel::SQL::BooleanExpression` created from this array, matching none of the conditions.

      [[:a, true]].sql_negate # SQL: a IS NOT TRUE
      [[:a, 1], [:b, [2, 3]]].sql_negate # SQL: a != 1 AND b NOT IN (2, 3)

[Source]

        # File lib/sequel/core_sql.rb, line 70
    70:   def sql_negate
    71:     sql_expr_if_all_two_pairs(:AND, true)
    72:   end

sql_or()

Return a `Sequel::SQL::BooleanExpression` created from this array, matching any of the conditions.

      [[:a, true]].sql_or # SQL: a IS TRUE
      [[:a, 1], [:b, [2, 3]]].sql_or # SQL: a = 1 OR b IN (2, 3)

[Source]

        # File lib/sequel/core_sql.rb, line 79
    79:   def sql_or
    80:     sql_expr_if_all_two_pairs(:OR)
    81:   end

sql_string_join(joiner=nil)

Return a `Sequel::SQL::BooleanExpression` representing an SQL string made up of the concatenation of this array‘s elements. If an argument is passed it is used in between each element of the array in the SQL concatenation.

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

[Source]

         # File lib/sequel/core_sql.rb, line 92
     92:   def sql_string_join(joiner=nil)
     93:     if joiner
     94:       args = zip([joiner]*length).flatten
     95:       args.pop
     96:     else
     97:       args = self
     98:     end
     99:     args = args.collect{|a| [Symbol, ::Sequel::SQL::Expression, ::Sequel::LiteralString, TrueClass, FalseClass, NilClass].any?{|c| a.is_a?(c)} ? a : a.to_s}
    100:     ::Sequel::SQL::StringExpression.new('||''||', *args)
    101:   end

sql_value_list()

Return a `Sequel::SQL::ValueList` created from this array. Used if this 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 ?', [[1, 2], [3, 4]].sql_value_list) # SQL: (a, b) IN ((1, 2), (3, 4))

[Source]

        # File lib/sequel/core_sql.rb, line 45
    45:   def sql_value_list
    46:     ::Sequel::SQL::ValueList.new(self)
    47:   end

~()

Return a `Sequel::SQL::BooleanExpression` created from this array, not matching all of the conditions.

      ~[[:a, true]] # SQL: a IS NOT TRUE
      ~[[:a, 1], [:b, [2, 3]]] # SQL: a != 1 OR b NOT IN (2, 3)

[Source]

        # File lib/sequel/core_sql.rb, line 10
    10:   def ~
    11:     sql_expr_if_all_two_pairs(:OR, true)
    12:   end

[Validate]