[Dbix-class] Resultset relation accessors

[Matt S Trout]

On Tue, May 26, 2009 at 01:49:05PM -0700, David Ihnen wrote:
> Sometimes I think i'm missing something obvious.
> 
> In my application, for instance, a holiday can be assigned to a group.
> 
> A group has many donors
> A donor might have many scheduled days
> A scheduled day is associated with a particular schedule
> 
> In this spot in my application, the operation is "update group schedule" .
> 
> I need to say "refresh all of the randomized scheduling for all of the 
> schedules related to all of the donors in the group this schedule is 
> on."  To do that I need a list of those schedules.
> 
> I first wrote that, for an update overload in my holiday class, like 
> this.  ($old is a hash ref to a copy of the get_columns from before the 
> update took place)
> 
> $self->groups->donors->schedule->ivr_schedule->search(
>            { 'date_start' => { '<=' => $old->{holiday} }
>            , -or =>
>              [ 'date_end' => { '>=' => $old->{holiday} }
>              , 'date_end' => undef
>              ]
>            } );
> 
> But I got an error, something like "No such method 'donors' on class 
> DBIx::Class::ResultSet"
> 
> So I rewrote it...
> 
> $self->groups->search_related('donors')->search_related('schedule')->search_related('ivr_schedule'
>       , ...yaddayadda...
> 
> and that worked.
> 
> So it leaves me wondering if I missed something fundamental here.  I 
> have an object which is a result set of a particular record type.  If I 
> want the records that are related to that result set - why would I have 
> to call 'related_resultset' - isn't "give me the related resulset" the 
> only thing I could mean when I call ->relationship on a result set?  If 
> that is so, why aren't there accessors created on the resultset for the 
> valid relations, to cut down on excessive verbosity that doesn't clarify?

I believe somebody tried that once.

Then they defined a relationship called 'next'.

Then they realised work would be involved and lost interest.

I don't see why it -can't- be done, just nobody's really tried. I reckon
you could do it as a schema component that wraps load_namespaces as a
start ...

-- 
        Matt S Trout         Catalyst and DBIx::Class consultancy with a clue
     Technical Director      and a commit bit: http://shadowcat.co.uk/catalyst/
 Shadowcat Systems Limited
  mst (@) shadowcat.co.uk        http://shadowcat.co.uk/blog/matt-s-trout/