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!
