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Array

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.

Public Instance Methods

all_two_pairs?() click to toggle source

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
# File lib/sequel/core_sql.rb, line 23
def all_two_pairs?
  !empty? && all?{|i| (Array === i) && (i.length == 2)}
end
case(*args) click to toggle source

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
# File lib/sequel/core_sql.rb, line 32
def case(*args)
  ::Sequel::SQL::CaseExpression.new(self, *args)
end
sql_array() click to toggle source

Deprecated alias for sql_value_list

Alias for: sql_value_list
sql_expr() click to toggle source

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)
# File lib/sequel/core_sql.rb, line 61
def sql_expr
  sql_expr_if_all_two_pairs
end
sql_negate() click to toggle source

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)
# File lib/sequel/core_sql.rb, line 70
def sql_negate
  sql_expr_if_all_two_pairs(:AND, true)
end
sql_or() click to toggle source

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)
# File lib/sequel/core_sql.rb, line 79
def sql_or
  sql_expr_if_all_two_pairs(:OR)
end
sql_string_join(joiner=nil) click to toggle source

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
# File lib/sequel/core_sql.rb, line 92
def sql_string_join(joiner=nil)
  if joiner
    args = zip([joiner]*length).flatten
    args.pop
  else
    args = self
  end
  args = args.collect{|a| [Symbol, ::Sequel::SQL::Expression, ::Sequel::LiteralString, TrueClass, FalseClass, NilClass].any?{|c| a.is_a?(c)} ? a : a.to_s}
  ::Sequel::SQL::StringExpression.new(:'||', *args)
end
sql_value_list() click to toggle source

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))
# File lib/sequel/core_sql.rb, line 45
def sql_value_list
  ::Sequel::SQL::ValueList.new(self)
end
Also aliased as: sql_array
~() click to toggle source

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

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