> -----Message d'origine-----
> De : Matt S Trout [mailto:[EMAIL PROTECTED]
> Envoyé : jeudi, 25. janvier 2007 11:59
> À : [email protected]
> Objet : Re: [Dbix-class] plat-form contest starting soon
>
>
> Which reminds me, you and I still need to sit down and chat
> about synergies.
>
> I reckon I could re-implement the documented interface of
> DBIx::DataModel atop DBIx::Class in ~3 days and it would
> actually be quite natural to do so, so I'm more and more
> suspecting the differences between the projects are largely
> in terms of how we conceptualise the interface rather than
> how we actually see the underlying domain.
Okay, now that plat-forms is over, let's start investigating some architectural
points. For the discussion I will assume a database schema similar to the one
in DBIx::Class::Manual::Example. In DBIx::DataModel, this would be written more
or less as
# Create a schema class
DBIx::DataModel->Schema('Music');
# Create table classes
# Perl_class DB_table Primary_key
# ---------- -------- -----------
Music->Table(qw/Artist artist artist_id /);
Music->Table(qw/Cd cd cd_id /);
Music->Table(qw/Track track track_id /);
# Declare UML associations
# Class role_name multiplicity
# ----- --------- ------------
Music->Association([qw/Artist artist 1 /],
[qw/Cd cds * /]);
Music->Composition([qw/Cd cd 1 /],
[qw/Track tracks 1..* /]);
Now if I want information about all recent cds and tracks of some artist, I
could write
my $rows = $someArtist->selectFromRoles(qw/cds tracks/)
->(-columns => [EMAIL PROTECTED],
-where => {year => {">" => 2004}},
-orderBy => 'year');
The equivalent SQL is
SELECT @some_column_list FROM cd INNER JOIN track ON cd.cd_id=track.cd_id
WHERE artist_id = $someArtist->{artist_id}
AND year > 2004
ORDER BY year
and each row returned by that query will be blessed into a new class
Music::AutoView::Cd_INNER_Track, created on the fly (if not already there),
and which inherits from both classes Cd and Track. Multiple inheritance
makes sense here because a row from that result set contains data from both
tables (Cd and Track).
Now I have two questions :
1) would such an idea (creating classes on the fly and using multiple
inheritance) be compatible with the architecture of DBIx::Class ? beneficial ?
disastrous ?
2) as far as I understand, DBIx::Class also manipulates the namespace
dynamically (loading classes and methods). Did you ever get in trouble when
serializing/deserializing such classes through Catalyst sessions, as it just
happened to me with DBIx::DataModel ? And if so, how did you solve it ?
Thanks in advance, L. Dami
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