class Sequel::SQL::CaseExpression
Represents an SQL CASE expression, used for conditional branching in SQL.
Attributes
An array of all two pairs with the first element specifying the condition and the second element specifying the result if the condition matches.
The default value if no conditions match.
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.
# File lib/sequel/sql.rb, line 1196 def initialize(conditions, default, expression=(no_expression=true; nil)) raise(Sequel::Error, 'CaseExpression conditions must be a hash or array of all two pairs') unless Sequel.condition_specifier?(conditions) @conditions = conditions.to_a.dup.freeze @default = default @expression = expression @no_expression = no_expression freeze end
Public Instance Methods
Whether to use an expression for this CASE expression.
# File lib/sequel/sql.rb, line 1206 def expression? !@no_expression end
Merge the CASE expression into the conditions, useful for databases that don't support CASE expressions.
# File lib/sequel/sql.rb, line 1212 def with_merged_expression if expression? e = expression CaseExpression.new(conditions.map{|c, r| [::Sequel::SQL::BooleanExpression.new(:'=', e, c), r]}, default) else self end end
Private Instance Methods
CaseExpression's initializer checks whether an argument was provided, to differentiate CASE WHEN from CASE NULL WHEN, so check if an expression was provided, and only include the expression in the inspect output if so.
# File lib/sequel/extensions/eval_inspect.rb, line 128 def inspect_args if expression? [:conditions, :default, :expression] else [:conditions, :default] end end