Hi Brice, I think something strange happened in the discussion group web page because it did not show me the existence of the message in which you linked to your solution. If I had seen that I would have known that you already found the way.
Cheers, Eric On Sunday, December 2, 2012 8:00:05 PM UTC-8, deBrice wrote: > > Hi Eric, > > Thank you, I actually used this documentation (even though they are only > many-to-many) and some other blog post to come up with this solution. Using > 0.7 I don't have event on Mixin so I had to find an alternative to event > attachment. BTW I'm pretty surprised by the speed of the event solution > provided by SQLAlchemy, as I always heard that event listener on DB object > were evil, but it turned out to almost add no overhead (test operated 2k > object creation). > > > On Sat, Dec 1, 2012 at 10:35 PM, Eric Ongerth <erico...@gmail.com<javascript:> > > wrote: > >> Hi Brice, >> >> Yours is another good case of the 'Generic Associations' or 'Polymorphic >> Association' pattern which comes up quite often. Here's a link to some >> docs that will get you going on a good solution that keeps the database >> normalized. >> >> >> http://docs.sqlalchemy.org/en/rel_0_8/orm/examples.html#generic-associations >> >> If that doesn't get you off and running, especially the example in >> discriminator_on_association.py, continue this thread or pop into the IRC >> channel. >> >> - ejo >> >> >> On Wednesday, November 28, 2012 1:20:52 PM UTC-8, deBrice wrote: >> >>> So here is my solution, >>> >>> https://gist.github.com/**4164619 <https://gist.github.com/4164619> >>> >>> Hope it helps others to get an insight on generic relation in SQLAlchemy. >>> >>> >>> On Tue, Nov 27, 2012 at 7:41 AM, Brice Leroy <bbrri...@gmail.com> wrote: >>> >>>> Thank you for the advice Robert. As I'm using flask I'm not sure how >>>> adaptable the ZCA would be. I'll try to understand the logic behind it and >>>> see if I can replicate it within my models. >>>> >>>> >>>> On Tue, Nov 27, 2012 at 7:12 AM, Robert Forkel >>>> <xrot...@googlemail.com>wrote: >>>> >>>>> hi, >>>>> i used to do something like this, i.e. adding information about urls, >>>>> views, etc. to sqlalchemy models, but found this to be inflexibel. Now >>>>> I keep URL-related information in the web app's routing component, and >>>>> to solve problems like the one you pose, I use zca adapters [1] (which >>>>> is easier when using pyramid, because you already have a component >>>>> registry available). So with this technology you'd register the same >>>>> FeedItem class as adapter for the various sqlalchemy models, which >>>>> means that at adaption time, the object to adapt will be passed to >>>>> you. >>>>> regards >>>>> robert >>>>> >>>>> [1] >>>>> http://www.muthukadan.net/**docs/zca.html<http://www.muthukadan.net/docs/zca.html> >>>>> >>>>> >>>>> On Tue, Nov 27, 2012 at 3:58 PM, Brice Leroy <bbrri...@gmail.com> >>>>> wrote: >>>>> > Hello everybody, >>>>> > >>>>> > It's about brainstorming on an elegant solution. I previously posted >>>>> this >>>>> > question on the Flask mailing list, and I got advised to post it on >>>>> > SQLAlchemy list... which make more sense I admit. So here is my >>>>> issue: >>>>> > >>>>> > I have N different classes: >>>>> > >>>>> > class Comment(Models): >>>>> > author_id = Integer >>>>> > comment = String >>>>> > creation_date = Date >>>>> > >>>>> > class Picture(Models): >>>>> > author_id = Integer >>>>> > image = File >>>>> > creation_date = Date >>>>> > ... >>>>> > >>>>> > now let say, I have a "follow" feature, allowing a user X to get >>>>> updates >>>>> > when Y (the user followed by X) does something (creepy...). >>>>> > >>>>> > So far I came up with something like that: >>>>> > >>>>> > class FeedItem(Model) >>>>> > table = String >>>>> > key = Integer >>>>> > creation_date = Date >>>>> > >>>>> > def url(self): >>>>> > #get object by querying self.table with self.key >>>>> > object = self.get_an_object(table=self.**table, key=self.key) >>>>> > return object.view_url >>>>> > >>>>> > and then add this property to Comment and Picture classes: >>>>> > >>>>> > @property >>>>> > def view_url(self): >>>>> > return url_for('view_function_name', self.id) >>>>> > >>>>> > - What would be your way of dealing with this kind of "open/generic" >>>>> > relationship items? >>>>> > >>>>> > - How would you manage automatic deletion of a FeedItem when the >>>>> object it >>>>> > points to get destroyed? (I'm thinking attaching function on delete >>>>> event to >>>>> > classes) >>>>> > >>>>> > - Would you create as many FeedItem per follower, or use a Table to >>>>> link >>>>> > them to followers, therefore deleting a FeedItem would automatically >>>>> delete >>>>> > the relation record from the Table.? >>>>> > >>>>> > Thank you, >>>>> > >>>>> > -- >>>>> > Brice >>>>> > >>>>> > -- >>>>> > You received this message because you are subscribed to the Google >>>>> Groups >>>>> > "sqlalchemy" group. >>>>> > To post to this group, send email to sqlal...@googlegroups.com. >>>>> >>>>> > To unsubscribe from this group, send email to >>>>> > sqlalchemy+...@**googlegroups.com. >>>>> >>>>> > For more options, visit this group at >>>>> > http://groups.google.com/**group/sqlalchemy?hl=en<http://groups.google.com/group/sqlalchemy?hl=en> >>>>> . >>>>> >>>>> -- >>>>> You received this message because you are subscribed to the Google >>>>> Groups "sqlalchemy" group. >>>>> To post to this group, send email to sqlal...@googlegroups.com. >>>>> To unsubscribe from this group, send email to sqlalchemy+...@** >>>>> googlegroups.com. >>>>> >>>>> For more options, visit this group at http://groups.google.com/** >>>>> group/sqlalchemy?hl=en<http://groups.google.com/group/sqlalchemy?hl=en> >>>>> . >>>>> >>>>> >>>> >>>> >>>> -- >>>> -- >>>> Brice >>>> >>>> >>> >>> >>> -- >>> Brice >>> >>> -- >> You received this message because you are subscribed to the Google Groups >> "sqlalchemy" group. >> To view this discussion on the web visit >> https://groups.google.com/d/msg/sqlalchemy/-/fIkNEtwTaH8J. >> >> To post to this group, send email to sqlal...@googlegroups.com<javascript:> >> . >> To unsubscribe from this group, send email to >> sqlalchemy+...@googlegroups.com <javascript:>. >> For more options, visit this group at >> http://groups.google.com/group/sqlalchemy?hl=en. >> > > > > -- > Brice > > -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. 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