[Catalyst] Best practices for extending DBIC model

[Ian.Docherty at nomura.com]

Eric
First of all this is a Catalyst mailing list, not really a DBIC mailing list. :)

However, if I understand your problem. Assuming you have created your DBIC schema outside of Catalyst, you will have classes something like MyApp::DB::Result::Clients and MyApp::DB::ResultSet::Clients

The MyApp::DB::ResultSet::Clients is where you create your code that does your grouped_clients method. E.g.

---------
package MyApp::DB::ResultSet::Clients;

sub grouped_clients {
    my ($self, $args) = @_;

    my @all_clients = $self->search($args);
    for my $client (@clients) {
        # massage your $client here
        ...
    }
    return @all_clients;
}

---------

Then you just call $c->model('DB::Clients')->grouped_clients;

Or have I missed your point?

Regards
Ian




From: Eric Wright [mailto:ewright at linescale.com] 
Sent: 14 July 2011 14:59
To: The elegant MVC web framework
Subject: [Catalyst] Best practices for extending DBIC model

Any input/comments on best practices for extending a DBIC model? I have a DBIC schema that for the most part does what I need it to do. I find where I need model specific enhancements I can easily extend the schema objects themselves keeping the data centric code out of my controller layer. What I'm struggling with is how best to handle things at a higher level - i.e. modifying the resultsets themselves. 

e.g. say I have a Clients table and I want to get *all* clients in the system and then massage them in some way. I cannot do this with simple SQL or DBIC joins. I can extend Clients.pm for level stuff but what I really need is a way to extend the DBIx::Class::ResultSet object that is returned by $c->model('DB::Clients') so that that I can perform something like the following:

my @clients = $c->model('DB::Clients')->grouped_clients;

I'm using Catalyst::Model::DBIC::Schema. Is there a preferred way to hook into the result set to customize things the way I need?

Or do I just create a new model altogether and call the schema from that model?

my @clients = $c->model('MyNewModel')->grouped_clients;

I dunno. The second method just seems a little kludgey to me unless I make it a complete wrapper around my DBIC schema. Any insight into how you guys build your apps would be most appreciated. 

Thanks!
Eric



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