How to add has_many association to two different model in rails migration?

Question

How can i accomplish this?

class User < ActiveRecord::Base     
  has_many :old_posts
  has_many :new_posts
end

I already have has_many relation to old_posts model. I would like to add another has_many relation to new_posts. The old_posts and new_posts are no way related. I'm in the process of refactoring my schema, I would like to support the 'old_posts' model for few months before I get rid of it totally.

I get this error in schema when I try to migrate

#Could not dump table "Users" because of 
following NoMethodError
#undefined method `[]' for nil:NilClass

What ur expecting when u call old_post and new_post? I mean conditions — krishnar, Oct 17 '17 at 12:55

krishnar · Answer 1 · 2017-10-17T13:18:07.263

1

You should specify conditions as both are referring to same model.
Mention model it's referring to explicitly as it won't identify model by default because of custom association names.

Update code like below

class User < ActiveRecord::Base
    has_many :old_posts, ->{where("created_at > ?", Time.now.end_of_day)}, class_name: 'Post', foreign_key: 'user_id'
    has_many :new_posts, ->{where("created_at < ?", Time.now.end_of_day)}, class_name: 'Post',foreign_key: 'user_id'
end

edited Oct 17 '17 at 13:18

answered Oct 17 '17 at 13:13

krishnar

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I'm using two different models 'old_posts' and 'new_posts' and these models now have different columns. – Lollypop Oct 17 '17 at 13:29
@Lollypop u mean different foreign key? – krishnar Oct 17 '17 at 14:02
No, it's completely different table and model. – Lollypop Oct 17 '17 at 14:14
1

@Lollypop why u created two models with same attributes ? – krishnar Oct 17 '17 at 14:24
Different columns and attributes they have. – Lollypop Oct 17 '17 at 14:42
@Lollypop then issue might be with your migration files. paste migration file which created recently for which u facing this issue. – krishnar Oct 17 '17 at 14:45
Thanks for your help. The schema dump issue was due to my ignorance. I was using bool instead of boolean. – Lollypop Oct 17 '17 at 15:25

How to add has_many association to two different model in rails migration?

1 Answers1