Rails ——使用不带 STI 的类型列？

我想使用一个名为 type的列而不调用单表继承(STI)-我只希望 type是一个包含 String的普通列。

如果 Rails 希望我只有一个表继承并抛出 The single-table inheritance mechanism failed to locate the subclass...This error is raised because the column 'type' is reserved for storing the class in case of inheritance.异常，我怎么能做到这一点呢？

有什么办法吗？

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小开

You can override the STI column name using set_inheritance_column:

class Pancakes < ActiveRecord::Base
set_inheritance_column 'something_you_will_not_use'
#...
end

So pick some column name that you won't use for anything and feed that to set_inheritance_column.

In newer versions of Rails you'd set inheritance_column to nil:

class Pancakes < ActiveRecord::Base
self.inheritance_column = nil
#...
end

小开

最佳答案

In Rails 3.1 set_inheritance_column is deprecated, also you can just use nil as a name, like this:

class Pancakes < ActiveRecord::Base
self.inheritance_column = nil
#...
end

小开

Rails 4.x

I encountered the problem in a Rails 4 app, but in Rails 4 the set_inheritance_column method does not exist at all so you can't use it.

The solution that worked for me was to disable the single table inheritance by overriding ActiveRecord’s inheritance_column method, like this:

class MyModel < ActiveRecord::Base


private


def self.inheritance_column
nil
end


end

Hope it helps!

小开

I know this question is rather old and this deviates a bit from the question you are asking, but what I always do whenever I feel the urge to name a column type or something_type is I search for a synonym of type and use that instead:

Here are a couple alternatives: kind, sort, variety, category, set, genre, species, order etc.

小开

If you want to do this for all models, you can stick this in an initializer.

ActiveSupport.on_load(:active_record) do
class ::ActiveRecord::Base
# disable STI to allow columns named "type"
self.inheritance_column = :_type_disabled
end
end