[Dbix-class] Left join "on" conditions

[Hu Hailin]

Look at this:

http://search.cpan.org/search?query=DBIx::Class::ResultSource::View

Take care possible performance issue.

I'm afraid it is impossible to implement conditional join using "?" in
DBIx::Class.

On Tue, Apr 5, 2011 at 12:40 PM, Brian E. Lozier <brian at massassi.com> wrote:
> I've recently begun a small project and decided to try DBIx::Class.  I
> am trying to use prefetch to bring in some related data but one of the
> joins should have an extra conditional on it.  Here is the search:
>
>    my $topics_rs = $schema->resultset('Topic')->search(
>        { forum_id => $forum_id },
>        {
>            prefetch => 'topic_view'
>        },
>    );
>
>
> The Topic.pm has a relationship:
>
> __PACKAGE__->might_have(topic_view =>
> 'Fan::DB::Schema::Result::TopicView', 'topic_id');
>
> And TopicView.pm has relationships:
>
> __PACKAGE__->belongs_to(post   => 'Fan::DB::Schema::Result::Post',  'post_id');
> __PACKAGE__->belongs_to(myuser => 'Fan::DB::Schema::Result::User',  'user_id');
>
> I'm trying to have the LEFT JOIN "on" condition include the user_id,
> so it gets something like this:
>
> SELECT * FROM topics LEFT JOIN topic_views ON (topics.topic_id =
> topic_views.topic_id AND topic_views.user_id = ?)
>
> The idea is that I'll always get the "topics" information and only get
> the "topic_views" information if topic_id matches and user_id matches
> whatever I pass in.
>
> Is there a way to run a search query like this?
>
> Thanks,
> Brian
>
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>



-- 
Sincerely,
Hu Hailin