Warning:Total Rails Newb (TRN). This should be a pretty basic question so I\'m hoping someone can spare a couple mins to help shed some light.
Let\'s say I have the
It will be useful: http://railscasts.com/episodes/47-two-many-to-many
class User < ActiveRecord::Base
has_many :members
has_many :groups, :through => :members
has_many :groups_as_owner, :class_name => "Group"
end
class Groups < ActiveRecord::Base
has_many :members
has_many :users, :through => :members
belongs_to :owner, :class_name => "User", :foreign_key => :user_id
end
class Member < ActiveRecord::Base
belongs_to :group
belongs_to :user
end
basically has_many-through associations are n:m associations (join-tables) that (shall) have more attributes than just the id's of the joined record ids...
so you have a table Groups (with an id), a table Users (with an id) and a table Members (no id, but user_id and group_id)
basically, what you did is nearly correct, just think about how you access a group from a user or vice versa....
a user would first look up its member information and through that member information get access to the group information ... and vice versa for a group
so you first set up
has_many :members
and then call
has_many :groups, :through => :members
all you need is
class User < ActiveRecord::Base
has_many :members
has_many :groups, :through => :members
end
class Groups < ActiveRecord::Base
has_many :members
has_many :users, :through => :members
end
class Member < ActiveRecord::Base
belongs_to :group
belongs_to :user
end
and you have another bug in your code above
you might want to use
user = group.users.new
instead of
user = group.user.new
Try this structure:
class User < ActiveRecord::Base
has_many :members
has_many :groups, :through => :members
end
class Groups < ActiveRecord::Base
has_many :members
has_many :users, :through => :members
end
class Member < ActiveRecord::Base
belongs_to :group
belongs_to :user
end
Also take a look at has_and_belongs_to_many
, if you don't need to do with class Member then you should use has_and_belongs_to_many
. In this case don't forget to create joining table in the database