Rails has_one not saving foreign key - ruby-on-rails

Question

I have the following tables
keyword
keyword_id - PK
description
status_id - FK
keyword_status
status_id - PK
description
Trying to model them in AR and when attempting to save in my test it's not saving the status ID in keyword. They are mapped as such:
class Keyword < ActiveRecord::Base
self.table_name = :keyword
self.primary_key = :KEYWORD_ID
attr_writer :description
attr_writer :keyword_status
has_one :keyword_status, foreign_key: :STATUS_ID
end
class KeywordStatus < ActiveRecord::Base
self.table_name = :keyword_status
self.primary_key = :STATUS_ID
end
and the code where it breaks (keyword status is populated by a fixture)
keyword = Keyword.new
keyword.description = "keyword#{n}"
keyword.keyword_status = KeywordStatus.first
keyword.save
When keyword.save is called i get cannot insert NULL into 'STATUS_ID' on table Keyword
NOTE: I cannot change any of the DDL

Answer 1

As dstarh said, the foreign key association is backwards. In your models you should only need:
class Keyword < ActiveRecord::Base
has_one :keyword_status
end
class KeywordStatus < ActiveRecord::Base
belongs_to :keyword, :foreign_key => "status_id"
end
For the association to work. Also, setting the KeywordStatus object up with a fixture before creating the associated object is a bit odd but will work if that is the behavior you need. Also, why not just use the foreign key keyword_id and let rails handle it for you?
Update if you want to use keyword_id instead of status_id as the foreign key:
the tables will be as such:
keyword
id - PK
description
keyword_status
id - PK
keyword_id - FK
description
And your models:
class Keyword < ActiveRecord::Base
has_one :keyword_status
end
class KeywordStatus < ActiveRecord::Base
belongs_to :keyword
end
Hope this helps!
Update 2: Given the tables cannot change the association has to be a bit backwards. I would recommend:
class Keyword < ActiveRecord::Base
belongs_to :keyword_status
end
class KeywordStatus < ActiveRecord::Base
has_many :keywords, :foreign_key => "status_id"
end
I used a has many as the association since from what has been said it looks like a keyword can share a status that another keyword has. This also means that you will have to do something like:
KeywordStatus.first.keywords = KeywordStatus.first.keywords.push(keyword)
KeywordStatus.save
instead of:
keyword.keyword_status = KeywordStatus.first
Which operates in the opposite direction than you want. As you can see this can get pretty confusing so if at all possible i would suggest writing a migration to change your tables (this can be done for tables that have existing data if that is the problem). Again I hope this helps!

Answer 2

You got the direction wrong. It should be keyword belongs_to status. The general rule is that the model that has the foreign key column belongs to the other model.