1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
|
module Arel
class Expression < Attribute
attributes :attribute, :function_sql, :alias, :ancestor
deriving :==
delegate :relation, :to => :attribute
alias_method :name, :alias
def initialize(attribute, function_sql, aliaz = nil, ancestor = nil)
@attribute, @function_sql, @alias, @ancestor = attribute, function_sql, aliaz, ancestor
end
def to_sql(formatter = Sql::SelectClause.new(relation))
formatter.expression self
end
def aggregation?
true
end
module Transformations
def as(aliaz)
Expression.new(attribute, function_sql, aliaz, self)
end
def bind(new_relation)
new_relation == relation ? self : Expression.new(attribute.bind(new_relation), function_sql, @alias, self)
end
def to_attribute
Attribute.new(relation, @alias, :ancestor => self)
end
end
include Transformations
end
end
|
