Class: Sequel::SQL::CaseExpression

Inherits:
GenericExpression show all
Defined in:
lib/sequel/sql.rb

Overview

Represents an SQL CASE expression, used for conditions.

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from StringMethods

#ilike, #like

Methods included from BooleanMethods

#~

Methods included from ComplexExpressionMethods

#extract, #sql_boolean, #sql_number, #sql_string

Methods included from OrderMethods

#asc, #desc

Methods included from CastMethods

#cast, #cast_as, #cast_numeric, #cast_string

Methods included from AliasMethods

#as

Methods inherited from Expression

#lit

Constructor Details

#initialize(conditions, default, expression = nil) ⇒ CaseExpression

Create an object with the given conditions and default value.

Raises:



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# File 'lib/sequel/sql.rb', line 488

def initialize(conditions, default, expression = nil)
  raise(Sequel::Error, 'CaseExpression conditions must be an array with all_two_pairs') unless Array === conditions and conditions.all_two_pairs?
  @conditions, @default, @expression = conditions, default, expression
end

Instance Attribute Details

#conditions ⇒ Object (readonly)

An array of all two pairs with the first element specifying the condition and the second element specifying the result.



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# File 'lib/sequel/sql.rb', line 478

def conditions
  @conditions
end

#default ⇒ Object (readonly)

The default value if no conditions are true



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# File 'lib/sequel/sql.rb', line 481

def default
  @default
end

#expression ⇒ Object (readonly)

The expression to test the conditions against



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# File 'lib/sequel/sql.rb', line 484

def expression
  @expression
end

Instance Method Details

#to_s(ds) ⇒ Object

Delegate the creation of the resulting SQL to the given dataset, since it may be database dependent.



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# File 'lib/sequel/sql.rb', line 495

def to_s(ds)
  ds.case_expression_sql(self)
end