Particular one-to-many relation

Question

I've got a Rails 3.1 app with a User model and a House model (this is like a group). I've set up a many-to-many relation with join model Membership between those two and there are methods to manages roles of a user in some house in the join model.

But my problem is that a User has only one house and not many. So I always have to do user.houses.first to get his house (I've set up a helper house which does that) but the design is not good so I've tried to put has_one :membership and has_one :house, :through => :membership instead of has_many :memberships and has_many :houses, :through => :memberships. But I got an error each time I try to access house from User.

How is it possible to set up this one-to-many relation with a join table like I was trying to do ?

Thank you in advance.

Im confused, in your DB model, can User have only one house or many houses? — Cygnusx1, Aug 16 '11 at 15:25

score 2 · Accepted Answer · answered Aug 16 '11 at 14:40

2

If you are going to use the one to many relation then association should be.

House

has_many :memberships

has_many :users, :through => :memberships

User

has_one :membership

has_one :house, :through => :membership

answered Aug 16 '11 at 14:40

HiteshRawal

445
2
10

I got an error message. But now it works after having restarted the server. – Cydonia7 Aug 16 '11 at 17:14

score 0 · Answer 2 · answered Aug 16 '11 at 14:57

0

I can't think of a way doing this with relations, however you could leave it as the plural and then just define house in users:

class User 
  has_many :memberships
  has_many :houses, :through => :memberships

  def house
    houses.first
  end
end

answered Aug 16 '11 at 14:57

Yule

9,668
3
51
72

I've tried to implement `house=` too with `delete_all` and `<<` but that's a little tricky, isn't it ? – Cydonia7 Aug 16 '11 at 14:58
Shouldn't be too dificult can you not just do houses = [new_house] – Yule Aug 16 '11 at 15:06
@Skydreamer it is tricky, but your schema is not a proper one for a one to many relationship. – Serabe Aug 16 '11 at 15:13

Particular one-to-many relation

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