Thank you so much!
I'll let you know!
P.S.:
just create the m2m table for the relationship as needed.
... and this is another evidence that my brain is not 100%
functional... Why didn't it occur to me? I dunno...
2011/3/23 Michael Bayer <mike...@zzzcomputing.com>:
>
> On Mar 23, 2011, at 5:47 PM, Hector Blanco wrote:
>
>> Hello everyone.
>>
>>
>> class BaseClass(object):
>> sqlRelationships_accelerator = None
>> internalAttrs_accelerator = None
>> properties_accelerator = None
>>
>> _id = Column("id", Integer, primary_key=True, key="id")
>>
>> @classmethod
>> def intermediate_allowed_user_groups_to_this(cls):
>> retval = None
>> try:
>> mapper = class_mapper(cls)
>> except ormExc.UnmappedClassError:
>> mapper = None
>>
>> if mapper and (mapper.local_table is not None):
>> try:
>> retval = getattr(Tables,
>>
>> ("intermediate_allowed_user_groups_to_%s"
>> % mapper.local_table.name))
>> except KeyError:
>> return None
>> return retval
>>
>> @declared_attr
>> def _allowedUserGroups(cls):
>> if cls:
>> intermediateTable =
>> cls.intermediate_allowed_user_groups_to_this()
>> if intermediateTable is not None:
>> return relationship("UserGroup",
>> secondary="intermediateTable",
>> primaryjoin="%s._id ==
>> intermediateTable.elementId" % cls.__name__,
>> secondaryjoin="UserGroup._id ==
>> intermediateTable.userGroupId",
>> collection_class=set
>> )
>> return None
>
> there's an enormous amount of complexity here for me to gather, its not
> runnable either, which basically means I'm going to skip it. In particular
> the whole digging into mappers and finding tables seems unnecessary, just
> create the m2m table for the relationship as needed.
>
> For the general case of "everyone has a many-to-many to X", a short example
> is attached. I hope to blog more about this kind of thing as an updated
> approach to that discussed in the old Polymorphic Associations post.
>
>
>
>
>
>
>
>
>
>>
>> def __hash__(self):
>> return int(self.id)
>>
>> def setId(self, id):
>> """Set id"""
>> self._id = int(id)
>>
>> def getId(self):
>> """Get id"""
>> return self._id
>>
>> def setAllowedUserGroups(self, allowedUserGroups):
>> self._allowedUserGroups = set(allowedUserGroups)
>>
>> def getAllowedUserGroups(self):
>> return self._allowedUserGroups
>>
>> @declared_attr
>> def allowedUserGroups(cls):
>> return synonym('_allowedUserGroups',
>> descriptor=property(cls.getAllowedUserGroups,
>> cls.setAllowedUserGroups))
>> ----------------------------------------
>>
>> The "intermediate_allowed_user_groups_to_this" classmethod tries to
>> grab the intermediate table from the Tables module based on the name
>> of the table where the actual instances of the class (descending from
>> BaseClass) are going to be stored. Going back to the Store class, the
>> __tablename__ is "stores". The
>> intermediate_allowed_user_groups_to_this method will try to grab a
>> table called "intermediate_allowed_user_groups_to_stores" (because
>> that is the intermediate table that would link UserGroups and Stores)
>>
>> * What I wanted to achieve:
>> To filter by userGroup, I just wanted to need adding an intermediate
>> table to the Tables module relating the UserGroup with the class to
>> filter (as I explained, if I wanted to filter "Store", which is stored
>> in the table
>> "stores", I just need to create a table called
>> "intermediate_allowed_user_groups_to_stores", or if I wanted to filter
>> "Foo", stored in the "foos" table, I would just need to create
>> "intermediate_allowed_user_groups_to_foos" and the baseclass, with its
>> declared_attribute relationship, helped by the
>> "intermediate_allowed_user_groups_to_this" would take care of the
>> rest.
>>
>> What I got:
>>
>> Traceback (most recent call last):
>> File "/home/ae/ev-cms/server/src/server/app.py", line 30, in __init__
>> SetupDB.setupDB()
>> File "/home/ae/ev-cms/backlib/database/SetupDB.py", line 26, in setupDB
>> populateWithSamples()
>> File "/home/ae/ev-cms/backlib/database/SetupDB.py", line 86, in
>> populateWithSamples
>> samples = Store.Store.getSamples()
>> File "/home/ae/ev-cms/backlib/store/Store.py", line 379, in getSamples
>> store = cls()
>> File "<string>", line 4, in __init__
>> File
>> "/home/ae/.buildout/eggs/SQLAlchemy-0.6.6-py2.6.egg/sqlalchemy/orm/state.py",
>> line 111, in initialize_instance
>> return manager.events.original_init(*mixed[1:], **kwargs)
>> File "/home/ae/ev-cms/backlib/store/Store.py", line 73, in __init__
>> self.allowedUserGroups = set()
>> File
>> "/home/ae/.buildout/eggs/SQLAlchemy-0.6.6-py2.6.egg/sqlalchemy/orm/attributes.py",
>> line 210, in __set__
>> return descriptor.__set__(instance, value)
>> File "/home/ae/ev-cms/backlib/database/BaseClass.py", line 80, in
>> setAllowedUserGroups
>> self._allowedUserGroups = set(allowedUserGroups)
>> AttributeError: can't set attribute
>>
>>
>> ... it didn't even get pass the Store.Store constructor... :-D
>>
>> class Store(BaseClass.BaseClass, declarative_base)
>> def __init__(self):
>> super(Store, self).__init__()
>> self.name = ""
>> self.allowedUserGroups = set() # Crack!
>>
>> If I remove the line self.allowedUserGroups = set() from the
>> constructor, I get this:
>> File "/home/ae/ev-cms/backlib/database/BaseClass.py", line 86, in
>> addAllowedUserGroup
>> self.allowedUserGroups.add(userGroup)
>> AttributeError: 'RelationshipProperty' object has no attribute 'add'
>>
>> I guess is not that easy... :-)
>>
>> I'm sure it's doable... but I don't know how... Any hint will be appreciated.
>>
>> As usual, thank you in advance
>>
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>
>
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