ActiveRecord STI: How can I break out of the parent class' default scope

Question

On Rails 3.1 RC6, given

class Animal < ActiveRecord::Base
  default_scope where(legs: 4)
end

The following does not work as expected:

class Man < Animal
  default_scope unscoped.where(legs: 2)
end

The resulting SQL statement looks like this:

SELECT * FROM animals WHERE legs = 4 AND legs = 2

How can I override the parent class' default scope entirely?

I've also tried the followings none of which work:

default_scope{ unscoped.where legs: 2 }
default_scope with_exclusive_scope{ legs: 2 }

score 9 · Accepted Answer · answered Mar 13 '12 at 08:50

9

I dug into Rails' source code and came up with a solution that works under Rails 3.1 (tested with activerecord 3.1.0.rc6):

class Animal < ActiveRecord::Base
  default_scope where(legs: 4)
end

class Man < Animal
  self.default_scopes = []
  default_scope where(legs: 2)
end

answered Mar 13 '12 at 08:50

Prathan Thananart

4,007
3
19
18

Seems that this works in Rails 3.0: self.default_scoping = [] – jemminger Apr 15 '13 at 22:49

score 0 · Answer 2 · answered May 19 '15 at 08:02

0

I'd found this and it helped me http://m.onkey.org/default-scopes-and-inheritance-to-the-rescue

answered May 19 '15 at 08:02

Arthur

145
1
9

This link is broken. Do you know where it might have moved to? – BananaNeil Apr 05 '17 at 20:15

ActiveRecord STI: How can I break out of the parent class' default scope

2 Answers2