I do not know about Django but in web2py you can do:
db.define_table('student',Field('name'))
db.define_table('faculty',Field('name'))
db.define_table('user',Field('type'),Field('ref_id'))
id1=db.student.insert(name="Max")
db.user.insert(type="student",ref_id=id1)
id2=db.faculty.insert(name="John")
db.user.insert(type="faculty",ref_id=id2)
for row in db().select(db.user.ALL):
print row.id, row.type, db[row.type][row.ref_id].name
outputs:
1, student, Max
2, faculty, John
Massimo
On Sep 6, 12:40 am, Yarko Tymciurak <[email protected]> wrote:
> correct -- there currently is no "reference generic" (and integer is the
> way);
>
> My question was: would it serve the community, be more obvious is there
> _was_ a
> "reference generic" so that these questions wouldn't need to come up....
>
> On Sun, Sep 6, 2009 at 12:00 AM, mdipierro <[email protected]> wrote:
>
> > Instead of 'reference generic' just use 'integer' and everything else
> > will work.
>
> > On Sep 5, 10:27 pm, Yarko Tymciurak <[email protected]> wrote:
> > > On Sat, Sep 5, 2009 at 9:40 PM, Matthew <[email protected]>
> > wrote:
>
> > > > Does Web2py have any concept of Polymorphic Associations like Ruby or
> > > > Generic Relations like Django?
>
> > > I think this is simple - rather than declaring a Field as a db.table
> > (ergo a
> > > reference), or a forward "reference" to another table, you can simply
> > define
> > > the field as was done before the forward reference syntax - as an integer
> > > field.
>
> > > We could make a generic reference to affect this - perhaps it would be
> > > easier for people to remember, e.g.:
>
> > > db.table_define( 'mytable',
> > > # ....
> > > Field( 'myref', 'reference generic' ); # DAL doesn't have this;
> > > should it so that generic references are explicitly named?
>
> > > If this seems too simple, remember the DAL makes a default ID, and it is
> > > numeric and autoincrementing (there are no classes to deal with).
>
> > > No you can simple do something like
>
> > > for for in db(db.othertable.id == db.mytable.myref).select():
> > > print row.value_of_interest
>
> > > So - there are your "Polymorphic Associations" or "Generic Relations" ---
> > > without the fancy names or complications - the ID is just an index - an
> > > integer, and uniformly so.
>
> > > - Yarko
>
> > > > This would be very beneficial for tagging or voting, because there is
> > > > usually a need to tag or vote on different models in the same
> > > > application.
>
> > > > Thanks,
> > > > Matthew
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"web2py-users" group.
To post to this group, send email to [email protected]
To unsubscribe from this group, send email to
[email protected]
For more options, visit this group at
http://groups.google.com/group/web2py?hl=en
-~----------~----~----~----~------~----~------~--~---
