[Dbix-class] Chaining multiple many-to-many relations

[Jean-François Stenuit]

Hi Felix,

This goes in the right direction :

my $rsApp = $rowUser->groups->search_related('bgroup_2_applications')->search_related('bapplication');

works and generate this query behind the scenes :
SELECT bapplication.id, bapplication.site_id, bapplication.code,
bapplication.comment FROM buser_2_group me JOIN bgroup bgroup ON
bgroup.id = me.group_id JOIN bgroup_2_application
bgroup_2_applications ON bgroup_2_applications.group_id = bgroup.id
JOIN bapplication bapplication ON bapplication.id =
bgroup_2_applications.application_id WHERE ( me.user_id = '8' )

groups->search_related('applications') does not work. Apparently,
search_related does not work with many-yo-many relationships.

Thanks for the hint,

-- Jean-François "Jef" Stenuit

On Wed, Dec 15, 2010 at 4:56 PM, Felix Antonius Wilhelm Ostmann
<ostmann at websuche.de> wrote:
> Test
> $user->groups->search_related('applications', {...});
> or
> $user->related_resultset('groups')->related_resultset('applications')->...
>
> Am 15.12.2010 16:18, schrieb Jean-François Stenuit:
>> Hi DBIC experts,
>>
>> Maybe a dumb question, maybe I'm doing it wrong, but I don't seem to
>> be able to chain two many-to-many relations.
>>
>> I'm re-writing (OO style) a RBAC system, where a user is part of a
>> group, and each group has access to a set of applications :
>>
>> user ----many-to-many---- group ----many-to-many----- application
>>
>> I'd like to use a shortcut of the form :
>> my $rsApplications=$rowUser->groups->applications
>>
>> But it does not seem to work. I get this error :  Can't locate object
>> method "applications" via package "DBIx::Class::ResultSet"
>>
>> Addressing the two many-to-many relationships independently works correctly.
>>
>> Is it at all possible to chain many-to-many relationships ?
>> DBIx::Class::Relationship doc has some hint about that "you cannot
>> call related_resultset and similar methods", so I suspect the answer
>> is negative. But I could be wrong.
>>
>> Another option would be to create a many-to-many relationship that
>> spawns all five tables ?
>>
>> Any hint welcome. Thanks in advance,
>>
>>
>> Jean-François "Jef" Stenuit
>>
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>
>
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>
> Felix Antonius Wilhelm Ostmann
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