On Jun 4, 2012, at 11:08 AM, Antonio Beamud Montero wrote:
> El 04/06/12 16:37, Michael Bayer escribió:
>> On Jun 1, 2012, at 12:30 PM, Antonio Beamud Montero wrote:
>>
>>> El 01/06/12 16:59, Michael Bayer escribió:
>>>> @appender needs to be a method that just accepts a mapped object to be
>>>> added to the collection. then, @internally_instrumented is needed to
>>>> prevent the collections system from placing additional insturmentation on
>>>> standard methods like __setitem__. Also building custom dictionary
>>>> collections is very difficult in any case (for me as well) so you were
>>>> close, and that's pretty good !
>>>>
>>> Only one more question.. Querying for example the ULine object, always give
>>> me the permissions for all objects.. Exists any way to filter that
>>> permissions by the User object I filter in the query, i.e. something like:
>>>
>>> objs =
>>> session.query(ULine).join(PermissionAssoc).join(Permission).join(User).filter(User.username
>>> == u'kratos').all()
>>> print objs[0].permissions
>>> ----
>>> MyMappedCollection({u'read': [<__main__.Permission object at
>>> 0xa04442c>,<__main__.Permission object at 0xa04454c>]})
>>> ----
>> haven't looked at your example again but you'd work it out in SQL first to
>> figure out the query you want, then convert to the ORM. Is the issue that
>> you don't know what the SQL is, or just how to get the Query to produce it ?
>
> The query is easy, my problem is with the property 'permissions', associated
> to a object. The definition in the PermissionAssoc is:
>
> permissions = orm.relationship(Permission,
> backref='association',
> lazy=False,
> collection_class=MyMappedCollection)
>
> But I don't know how to configure this relationship to filter by a user (I
> don't know if it's possible). Like a dynamic relationship (to not query
> always all the permissions for all user associated to this object).
if the relationship is not dynamic, you need to use it in a larger query and
filter there:
query(PermissionAssoc).join(PermissionAssoc.permission).join(Permission.user).filter(User.something==something)
if you want an attribute to do this, then you'd use a @property or method on
PermissionAssoc, get the session from object_session(self).
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