Re: one to one relationship revisited (has_own)

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On Thu, 2005-01-20 at 14:26 -0800, Peter Speltz wrote:
> i think it would be cool if programs could distinguish if has_a relationships
> were one to one or many to one. AsForm treats them as many to one by making a
> select box of all existing foreign objects. 

I don't see the difference, from the side of the table that is embedding
another table's ID.  It can never put the ID of more than one other
object in that column.

True one-to-one relationships are not common, since they could always be
put into the same table.  The current method people usually use for them
is might_have, where this row's ID is stored in the other table's
column.

>  Then AsForm could instead of making a select box of all phones, make input
> box(s) for column(s) in phone. 

Sounds more and more like a might_have.  Or maybe just a custom
presentation that a generic tool like AsForm shouldn't be asked to
create.

> Furthermore, i thought that create and update may be able to automatically
> create and update phone:
> 
> $prsn = Person->create( {...., phone_id => {...} } );

That could be added to might_have.  I think that would be useful.

> Delete however would cascade like has_many.

It already does with might_have.

- Perrin