Rails - Jan 2006 - Re: Some advice on DB modeling

I have more or less the same problem. I''m trying to build a system
where
users can enter their friends. But the solutions seems not to work for me.

I used same sql:

CREATE TABLE `friends` (
    `user_id` int(11) NOT NULL default ''0'',
    `friend_id` int(11) NOT NULL default ''0'',
    KEY `user_id` (`user_id`),
    KEY `friend_id` (`friend_id`),
    CONSTRAINT `friends_ibfk_1` FOREIGN KEY (`user_id`) REFERENCES 
`users`  (`id`),
    CONSTRAINT `friends_ibfk_2` FOREIGN KEY (`friend_id`) REFERENCES 
`users` (`id`)
)

My user.rb looks like this:

class User < ActiveRecord::Base
    has_and_belongs_to_many :friends, :join_table =>
''friends'',
:class_name => ''User'', :foreign_key =>
''friend_id''

   has_and_belongs_to_many :friends_of, :join_table =>
''friends'',
:class_name => ''User'', :foreign_key =>
''user_id'',
:association_foreign_key => ''friend_id''

   attr_accessor :new_password
   attr_accessor :friends
   attr_accessor :friends_of

...
end

But when I use user.friends or user.friends_of they always return nil 
even after I entered some data in the db manually. There are no errors 
in the logfile...

Any ideas?

thanks
Frank

On 1/6/06, Frank Spychalski <rails-ml@spychalski.de>
wrote:
> I have more or less the same problem. I''m trying to build a system
where
> users can enter their friends. But the solutions seems not to work for me.
>
> I used same sql:
>
> CREATE TABLE `friends` (
>     `user_id` int(11) NOT NULL default ''0'',
>     `friend_id` int(11) NOT NULL default ''0'',
>     KEY `user_id` (`user_id`),
>     KEY `friend_id` (`friend_id`),
>     CONSTRAINT `friends_ibfk_1` FOREIGN KEY (`user_id`) REFERENCES
> `users`  (`id`),
>     CONSTRAINT `friends_ibfk_2` FOREIGN KEY (`friend_id`) REFERENCES
> `users` (`id`)
> )
>
> My user.rb looks like this:
>
> class User < ActiveRecord::Base
>     has_and_belongs_to_many :friends, :join_table =>
''friends'',
> :class_name => ''User'', :foreign_key =>
''friend_id''
>
>    has_and_belongs_to_many :friends_of, :join_table =>
''friends'',
> :class_name => ''User'', :foreign_key =>
''user_id'',
> :association_foreign_key => ''friend_id''
>
>    attr_accessor :new_password
>    attr_accessor :friends
>    attr_accessor :friends_of
>
> ...
> end
>
> But when I use user.friends or user.friends_of they always return nil
> even after I entered some data in the db manually. There are no errors
> in the logfile...
>
> Any ideas?
>
You don''t need attr_accessors for associations.  has_many :whatevers
creates the ''whatevers'' method for you.

P.S. You can do multiple attr_accessors on one line, separated with
commas, if you want.
e.g. attr_accessor :thing1, :thing2, :thing3

Wilson Bilkovich wrote:
> 
> You don''t need attr_accessors for associations.  has_many
:whatevers
> creates the ''whatevers'' method for you.
> 
> P.S. You can do multiple attr_accessors on one line, separated with
> commas, if you want.
> e.g. attr_accessor :thing1, :thing2, :thing3
thanks - the accessors where leftovers from a previous try and I forgot 
to remove them...

Frank