Rails - Apr 2005 - Validation problem with active record: Association Type Mismatch

Hi everyone,  I''m starting on my first rails project and I have a
problem that I''m sure has a simple solution.  I have two models, an
address model and a state model.  The address belongs_to :state,
foreign_key=>"state" and validate_associated :state

I have new & edit controllers for address which contain a drop down
list for the state choice.  My list was created with
options_from_collection_for_select @states, "id", "name",
@address.state

When I go to the new or edit page, everything looks good.  However,
when I submit my new record (or edit an existing one) I get an
ActiveRecord AssociationTypeMismatch Expected type State but found
string instead.  I can see that the proper ID is being returned, it''s
just being read by ruby as a string and I''m not sure how to cast it.
I tried using the various before_validation functions, but they never
seem to be called (I was explicitly throwing exceptions inside them to
make sure).

I''m totally stuck.

--Pat

Pat Mac wrote:
>I have new & edit controllers for address which contain a drop down
>list for the state choice.  My list was created with
>options_from_collection_for_select @states, "id",
"name",
>@address.state
>
>When I go to the new or edit page, everything looks good.  However,
>when I submit my new record (or edit an existing one) I get an
>ActiveRecord AssociationTypeMismatch Expected type State but found
>string instead.  I can see that the proper ID is being returned,
it''s
>  
>
what''s the name of your select field? If you name it like your
"state"
attribute, rails will try to assign the "id" string to this attribute 
which fails, because it expects a state object. If you name it after the 
column name (e.g. "state_id") it should work.

Sebastian

On Apr 5, 2005 12:17 PM, Sebastian Kanthak
<sebastian.kanthak-ZS8b95Whz3sUSW6y5lq3GQ@public.gmane.org>
wrote:
> Pat Mac wrote:
> 
> >I have new & edit controllers for address which contain a drop down
> >list for the state choice.  My list was created with
> >options_from_collection_for_select @states, "id",
"name",
> >@address.state
> >
> >When I go to the new or edit page, everything looks good.  However,
> >when I submit my new record (or edit an existing one) I get an
> >ActiveRecord AssociationTypeMismatch Expected type State but found
> >string instead.  I can see that the proper ID is being returned,
it''s
> >
> >
> what''s the name of your select field? If you name it like your
"state"
> attribute, rails will try to assign the "id" string to this
attribute
> which fails, because it expects a state object. If you name it after the
> column name (e.g. "state_id") it should work.
> 
> Sebastian
> 
> _______________________________________________
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> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
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> 
Interesting... shouldn''t the :foreign_key=>"state" allow
this to work?
 Changing everything from state to state_id worked (including the
database), but I would hope I don''t need to rename all of my foreign
key columns just for rails.

BTW.. sorry for the multiple posts.  The "postmaster" spam was making
me think my messages were being bounced.

On 5.4.2005, at 23:10, Pat Mac wrote:
>>
> Interesting... shouldn''t the :foreign_key=>"state"
allow this to work?
>  Changing everything from state to state_id worked (including the
> database), but I would hope I don''t need to rename all of my
foreign
> key columns just for rails.
The problem here is that when you declare that address belongs_to 
:state, @address.state will be automatically used as a method to get to 
that specific State object. Therefore Rails can''t know that
you''re in
fact referring to a column named "state" instead of the object.

You can work around this by using something else as your association 
name:

class Address ...
	belongs_to :home_state, :class_name => "state", :foreign_key =>
"state"
end

Now you can use @address.home_state which refers to the object and 
@address.state which refers to the foreign key field. That way you 
shouldn''t have to change your existing databases.

HTH,
Jarkko
>
> BTW.. sorry for the multiple posts.  The "postmaster" spam was
making
> me think my messages were being bounced.
> _______________________________________________
> Rails mailing list
> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
--
Jarkko Laine
http://jlaine.net
http://odesign.fi


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