ActiveRecord STI：如何摆脱父类？默认范围

发布于 2024-12-02 04:40:25 字数 497 浏览 3 评论 0原文

在 Rails 3.1 RC6 上，给定

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

以下内容无法按预期工作：

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

生成的 SQL 语句如下所示：

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

如何完全覆盖父类的默认范围？

我还尝试了以下方法，但均无效：

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

原文

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 }

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孤者何惧 2024-12-09 04:40:25

我深入研究了 Rails 的源代码，并提出了一个在 Rails 3.1 下工作的解决方案（使用 activerecord 3.1.0.rc6 进行测试）：

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

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

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

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