Class Sequel::SQL::CaseExpression
In: lib/sequel/extensions/eval_inspect.rb
lib/sequel/sql.rb
Parent: Object

Represents an SQL CASE expression, used for conditional branching in SQL.

Methods

Attributes

conditions  [R]  An array of all two pairs with the first element specifying the condition and the second element specifying the result if the condition matches.
default  [R]  The default value if no conditions match.
expression  [R]  The expression to test the conditions against

Public Class methods

Create an object with the given conditions and default value. An expression can be provided to test each condition against, instead of having all conditions represent their own boolean expression.

[Source]

      # File lib/sequel/sql.rb, line 1069
1069:       def initialize(conditions, default, expression=(no_expression=true; nil))
1070:         raise(Sequel::Error, 'CaseExpression conditions must be a hash or array of all two pairs') unless Sequel.condition_specifier?(conditions)
1071:         @conditions, @default, @expression, @no_expression = conditions.to_a, default, expression, no_expression
1072:       end

Public Instance methods

Whether to use an expression for this CASE expression.

[Source]

      # File lib/sequel/sql.rb, line 1075
1075:       def expression?
1076:         !@no_expression
1077:       end

Merge the CASE expression into the conditions, useful for databases that don‘t support CASE expressions.

[Source]

      # File lib/sequel/sql.rb, line 1081
1081:       def with_merged_expression
1082:         if expression?
1083:           e = expression
1084:           CaseExpression.new(conditions.map{|c, r| [::Sequel::SQL::BooleanExpression.new('=''=', e, c), r]}, default)
1085:         else
1086:           self
1087:         end
1088:       end

[Validate]