Martyn Elmy-liddiard wrote:> Another newbie question I fear but help as always appreciated.
>
> I have a tools table and a controls table and for each
''tool'' I allow
> user to specify upto 3 controls.
>
> So the Tools table is :-
> id
> desc
> control_id1
> control_id2
> control_id3
>
> and the Controls table is:
> id
> controldesc
>
> I have linked the tables in their models with
> Tools
> belongs_to :control
>
> and Control
> has_many :tools
>
> When I display the Tools rows I want to display the
''desc'' column from
> the Controls table for each of the control_id1, control_id2 and
> control_id3.
>
> Is this possible or is a relationship link only available on a single
> column in the Tools table that must be called
''control_id'' ?
It is possible -- check out the options on belongs_to and has_many --
but it''s inadvisable. In general, it is *very* bad practice to have a
database design that has repeating fields such as your coltrol_id[1-3]
-- it will create all sorts of problems down the road. I think you
should be using a has_and_belongs_to_many relationship between controls
and tools.
>
> Hope this makes sense.
>
> Thanks
Best,
--
Marnen Laibow-Koser
http://www.marnen.org
marnen-sbuyVjPbboAdnm+yROfE0A@public.gmane.org
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