Save inherited object to separate collection in Mongoid

Question

I read up to inheritance in mongoid and it seems that all inherited classes will save in the base class, e.g.

class BaseClass
end

class ChildClass1 < BaseClass
end

class ChildClass2 < BaseClass
end

It seems that all these store in the BaseClass collection.

I actually want them to store in separate collections, e.g. ChildClass1 - collection and ChildClass2 - collection.

According to discussion on [this](https://github.com/mongoid/mongoid/issues/1133) issue I'd assume that there is no way to store subclasses in a separate collections. You can go with mixins instead of inheritance as durran suggests in this issue. — KL-7, Mar 15 '12 at 19:06
Is there any problem with using this: self.collection_name = "account"? Obviously my goal is to keep my collections small. Is that a good idea anyway? — Boenne, Mar 16 '12 at 00:36
I found the good answer here http://stackoverflow.com/questions/10704310/mongoid-store-in-produces-random-results — Arugin, May 28 '14 at 09:30

Ronna · Answer 1 · 2014-02-23T14:22:48.710

4

I realise this was posted a year ago, but this might be what you were looking for:

class BaseClass
  include Mongoid::Document
  def self.inherited(subclass)
    super
    subclass.store_in subclass.to_s.tableize
  end
end

class ChildClass1 < BaseClass
end

class ChildClass2 < BaseClass
end

edited Feb 23 '14 at 14:22

answered Feb 20 '14 at 09:11

Ronna

1,150
14
24

score 4 · Answer 2 · answered May 17 '17 at 14:22

4

Please try this approach:

module Base
  extend ActiveSupport::Concern

  include Mongoid::Document
  include Mongoid::Timestamps

  included do
    # Common code goes here.
  end
end

class ChildClass1
  include Base
end

class ChildClass2
  include Base
end

I do this in my Rails 5 app and it works for sure.

answered May 17 '17 at 14:22

Slavik Shynkarenko

376
1
5
8

1

exactly what I was looking for. Testing/Working in a non-rails app – Dishcandanty Apr 13 '18 at 23:18

Assaf Faybish · Answer 3 · 2018-08-29T16:11:44.210

I encountered the same problem and did not find a good solution on the web. After few attempts, I developed a solution:

class A
  include Mongoid::Document
  include Mongoid::Timestamps
  ...
end


class B < A
  def self.collection_name
    :your_collection_name_1
  end
  ...
end


class C < A
  def self.collection_name
    :your_collection_name_2
  end 
  ...
end

Before any access to mongo collection, mongoid gets the collection name from 'collection_name' method.

This way, I override the method 'collection_name' of mongoid class, which returns the collection name (instead of the name of the base class with 's': 'As')

So, all the write (or read) commands from class B will insert (select) into 'your_collection_name_1' collection and class C will insert into 'your_collection_name_2' collection.

score 3 · Answer 4 · answered Mar 16 '12 at 09:20

3

It's impossible to do that. Because it's the concept of the STI In Mongoid like explain by Durran the Mongoid creator

If you really want save in several collection you need use Module include like :

class BaseClass
  include MyModule
end

class ChildClass1
  include MyModule
end

class ChildClass2
  include MyModule
end

answered Mar 16 '12 at 09:20

shingara

46,608
11
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Thanks, that's good input. What about this? self.collection_name = "account"? is there any catch? – Boenne Mar 16 '12 at 17:44
1

you need use the class method `store_in` to define in which collection you want save your object – shingara Mar 17 '12 at 08:46

Save inherited object to separate collection in Mongoid

4 Answers4