Thanks!
On Thu, Jun 24, 2010 at 2:27 PM, mdipierro <mdipie...@cs.depaul.edu> wrote:
> thinking about how to handle this...
>
> On Jun 22, 12:56 pm, Carles Gonzalez <carle...@gmail.com> wrote:
>> My english is horrible, an maybe it wasn't clear, but that was exactly
>> my problem :).
>>
>> Currently i'm looking at the code massimo told me about but i think
>> that the problem isn't here.
>>
>> I explain: the parent is assigned when the child entity is created (at
>> the constructor level), to ensure all entities on the same group are
>> stored together (or close), that way transactions are feasible.
>>
>> I don't think i'm capable of doing that right now, but my proposed
>> soultion (just an idea) is to extend the field definition syntax for
>> reference fields, adding an atribute to indicate this tipe of
>> relationship.
>>
>> Example (blatantly stolen from the book):
>>
>> db.define_table('person',
>> Field('name'))
>> db.define_table('dog',
>> Field('name'),
>> Field('owner', db.person, relationship="parent"))
>>
>> On SQL databases that attribute would be ignored, but in GAE web2py
>> would enforce the parent relationship at creation and dog[id].parent
>> would return the result of dog_instance.parent()
>>
>> I don't know if this is feasible or if i'm total crazy (an option to
>> consider). Opinions?
>>
>> On Tue, Jun 22, 2010 at 1:42 AM, Matt <mjwat...@gmail.com> wrote:
>> > Any chance this could be considered as well?
>>
>> > Currently the DAL doesn't allow you to set the parent which is
>> > required for GAE entity groups.
>>
>> >http://groups.google.com/group/web2py/browse_thread/thread/3c11deb2bf...
>>
>> > On Jun 22, 7:35 am, Carles <carle...@gmail.com> wrote:
>> >> Ok, I'll try.
>>
>> >> Carles
>>
>> >> El 21/06/2010, a las 19:03, mdipierro <mdipie...@cs.depaul.edu> escribió:
>>
>> >> > The only file you need to look into is gluon/contrib/gql.py
>>
>> >> > specifically the select() function which calls filter returns the Rows
>> >> > object
>>
>> >> > On Jun 21, 11:55 am, Carles Gonzalez <carle...@gmail.com> wrote:
>> >> >> Ok, thanks! I would like to make the patch myself, but the innards of
>> >> >> web2py are somewhat complex...
>>
>> >> >> Thanks again, Carles.
>>
>> >> >> On Mon, Jun 21, 2010 at 6:43 PM, mdipierro <mdipie...@cs.depaul.edu>
>> >> >> wrote:
>> >> >>> Probably it would not be hard to implement. I will look into this next
>> >> >>> week but if somebody sends me a patch before that I will take it.
>>
>> >> >>> Massimo
>>
>> >> >>> On Jun 21, 9:25 am, Carles Gonzalez <carle...@gmail.com> wrote:
>> >> >>>> Hi,
>>
>> >> >>>> I have developed some applications in web2py, and 2 are running
>> >> >>>> currently in gae, but now i have serious problem.
>>
>> >> >>>> My current project is a social application, and when i design
>> >> >>>> (example) the tables to make an user follow the actions other user
>> >> >>>> (twitter like) I find that many-to-many relationships in app-engine
>> >> >>>> are not easily supported.
>>
>> >> >>>> From my understanding using the tools present in web2py right i would
>> >> >>>> need to do a lot of processing in memory, an that would hurt
>> >> >>>> performance greatly.
>>
>> >> >>>> The pattern proposed by app store developers uses lists and "parent"
>> >> >>>> relationship:
>>
>> >> >>>> class Message(db.Model):
>> >> >>>> sender = db.StringProperty()
>> >> >>>> body = db.TextProperty()
>>
>> >> >>>> class MessageIndex(db.Model):
>> >> >>>> receivers = db.StringListProperty()
>>
>> >> >>>> indexes = MessageIndex.all(keys_only = True).filter('receivers = ',
>> >> >>>> user_id)
>> >> >>>> keys = [k.parent() for k in indexes)
>> >> >>>> messages = db.get(keys)
>>
>> >> >>>> For using that pattern in web2py I would need a method for specifying
>> >> >>>> the parent of a model instance. Can I specify that relationship using
>> >> >>>> any method I don't know? If not, would it be hard to implement?
>>
>> >> >>>> Thanks in advance!
