Re: Class::DBI Intro

[mojotoad]

in reply to Class::DBI Intro

Nice tutorial. ++

A number of things I'd be curious to see added:

• Autocreation of table classes via Class::DBI::mysql and ilk. (Class::DBI::Loader seems to be aimed at mod_perl? If not, how do these differ?)
• Some exposition on handling joins via the has_many() call with mapping syntax, i.e. from the docs:

  Music::CD->has_many(styles => [ 'Music::StyleRef' => 'style' ]);

  is identical to
  

  Music::CD->has_many(_style_refs => 'Music::StyleRef');
      sub styles { 
          my $self = shift;
          return map $_->style, $self->_style_refs;
      }
  

  (but note that your join table still requires a primary key)

• Real bridging of object heirarchies into relational databases using toys such as Class::DBI::SAK, which integrate lots of approaches such as that taken by Class::Tangram (or at least, so I hear)

Good stuff,
Matt

[salvadors]

(but note that your join table still requires a primary key)

Actually, it doesn't always. As long as the relationship is unique, the cross-reference itself can be treated as a multi-column primary key, even if it isn't defined as such in the database.

Strange things can happen with this if you step off the (admittedly very narrow) beaten path, but for general cross-referencing it seems to work just fine.

Tony

[mojotoad]

Actually, it doesn't always. As long as the relationship is unique, the cross-reference itself can be treated as a multi-column primary key, even if it isn't defined as such in the database.

Can you give an example? I'm still learning about Class::DBI, but thus far I have not found a way to avoid it claiming the first column as a primary key (in the absence of such a declaration in the DB table itself).

Matt