Rails - Feb 2005 - Reusing the same table in different roles

Couldn''t think of a better subject line :-)

I have a table called Ecrs. That table has requester_id and approver_id 
fields. Both of these fields should be linked to the Users table.
Currently I have:

app/models/ecr.rb
class Ecr < ActiveRecord::Base
   belongs_to :requester, :class_name => ''User'',
:foreign_key =>
''requester_id''
   belongs_to :part
   belongs_to :level
   has_and_belongs_to_many :approver, :class_name =>
''User'',
:foreign_key => ''approver_id''
end

app/models/user.rb
class User < ActiveRecord::Base
   has_many :ecrs, :class_name => "User", :foreign_key =>
"requester_id"
   has_and_belongs_to_many :ecrs, :class_name => "User",
:foreign_key =>
"approver_id"
[...]
end

Rails complained of not having an ecrs_users table, so I created one:

id	int
ecr_id	int
user_id	int

This got the requester working. @ecr.requester is valid data.
Then rails complained that approver_id wasn''t in the ecrs_users table, 
so I added the field.
The table now looks like this:
id	int
ecr_id	int
user_id	int
approver_id	int

Eventually, the Users table will (I hope) be filtered based on fields 
like can_approve and can_request, so that only
can_approve=1 Users can approve, etc.

Is this the proper way to do this?
It seems a bit kludgey since the ecrs_users table is doing double duty.

Thanks for any advice!

Regards,
   JJ

On 8.2.2005, at 16:28, John Johnson wrote:
>
> app/models/ecr.rb
> class Ecr < ActiveRecord::Base
>   belongs_to :requester, :class_name => ''User'',
:foreign_key =>
> ''requester_id''
>   belongs_to :part
>   belongs_to :level
>   has_and_belongs_to_many :approver, :class_name =>
''User'',
> :foreign_key => ''approver_id''
> end
>
This should help:
  has_and_belongs_to_many :approvers, :class_name => ''User''

>
> app/models/user.rb
> class User < ActiveRecord::Base
>   has_many :ecrs, :class_name => "User", :foreign_key =>
"requester_id"
You can''t use symbol :ecrs twice here. Change either of them, e.g like 
this:

   has_many :requestees, :class_name => "Ecr", :foreign_key => 
"requester_id"

(here you have to assign the :class_name explicitly because your 
association name (:requester) is not the same as the class name 
("Ecr"). However, it should be the other side of the association, i.e.
Ecr, not User)

>   has_and_belongs_to_many :ecrs, :class_name => "User",
:foreign_key
> => "approver_id"
  has_and_belongs_to_many :ecrs

(you don''t need to specify anything else. :class_name =>
"User" is
plain wrong, it should be Ecr. However, you can leave it away since 
rails can guess the name from ":ecrs". Foreign key means the foreign 
key in ecrs_users table that refers to users table. As it is user_id, 
you don''t have to say it explicitly)

Other way would be to use this:

  has_and_belongs_to_many :approvees, :class_name => "Ecr"

Now your ecrs_users table can be as simple as

ecr_id int
user_id int

> Eventually, the Users table will (I hope) be filtered based on fields 
> like can_approve and can_request, so that only
> can_approve=1 Users can approve, etc.
>
> Is this the proper way to do this?
> It seems a bit kludgey since the ecrs_users table is doing double duty.
Shouldn''t do anymore. Hope you can get something off my hieroglyphs. If
not, drop a line or step into #rubyonrails on irc.freenode.net.

//jarkko
>
> Thanks for any advice!
>
> Regards,
>   JJ
>
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>
--
Jarkko Laine
http://jlaine.net
http://odesign.fi


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On 08-Feb-2005, at 10:16, Jarkko Laine wrote:
>
> On 8.2.2005, at 16:28, John Johnson wrote:
>>
>> app/models/ecr.rb
>> class Ecr < ActiveRecord::Base
>>
That was a great help, thanks!

Regards,
   JJ