many-to-many relationship and sorting

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So something like that would do the trick?

my @films =3D map { $_->film } Role->search( actor =3D> $actor, {order_by=
 =3D> 'name'} );

-Alex


-----Urspr=FCngliche Nachricht-----
Von: William Ross [mailto:will@xxxxxxx.xxx]=20
Gesendet: Mittwoch, 9. M=E4rz 2005 12:14
An: Hartmaier Alexander
Cc: cdbi-talk@xxxxxx.xxxxx.xxx
Betreff: Re: many-to-many relationship and sorting

On 9 Mar 2005, at 10:29, Hartmaier Alexander wrote:

> How does the mapping method work internally?
> I thought it retrieves all id's of the foreign class (table) with a=20
> single sql statement...then only an ORDER BY sql clause would be=20
> needed...

The has_many(x =3D> [y =3D> z]) shortcut you're using doesn't change the=20=

SQL generated by has_many: it just adds an extra inflation step after=20
the foreign ids have been retrieved from the linking table. The=20
destination table in a m2m relationship is never touched, so there is=20
no chance to order the results by something in that table.

If you look at Class::DBI::Relationship::HasMany->_hm_run_search,=20
you'll see that it just calls search() on the linking class. So with=20
this:

	Actor->has_many(films =3D> [ Role =3D> 'film' ]);

these two statements are _exactly_ the same:

	my @films =3D $actor->films;
	my @films =3D map { $_->film } Role->search( actor =3D> $actor );

I thought Matt's HasManytoMany looked good: thoughtful and=20
well-constructed, and it will do what you need. the documentation is a=20=

bit sparse, though :)

best

will


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