On Sat, Aug 21, 2010 at 01:45:48PM -0400, Michael Bayer wrote:
> > columns in a property
> > column = prop.columns[0]
> >
> > props = []
> > for pr in mapper.iterate_properties:
> > if isinstance(pr, properties.RelationProperty):
> > if pr.direction.name in ('MANYTOONE',):
> > for col in pr.local_remote_pairs[0]:
> > # I can't use col in p.local_remote_pairs
> > # as it uses 'col == p.local_remote_pairs' that evaluates
> > # to a BinaryExpression
> > if column is col:
> > try:
> > if pr.backref.prop.cascade.delete_orphan:
> > props += [pr]
> > except AttributeError, e:
> > pass
> > return tuple(props)
> >
> > This fails in sqla 0.6 as pr.backref is empty. Which is the correct
> > way to
> > get the properties that have a backref that have cascade with
> > delete_orphan?
>
>
> why not put some "info" on the director_id column (i.e. Column(....,
> info={'foo':'bar'}) ) that gives your application the information what you
> need in a succinct and direct way. There's no public API that links
> relationships to backrefs and the poking through lists of columns is hacky
> too. I could tell you where they're linked but it can change at any time.
I wasn't aware of 'info' option. I do appreciate how easy it is to implement
it this way. On the other hand the other approch didn't even need special
configuration.
Info option is clearly very handy. At the moment I implemented an image
field in sqlkit, (that's just a bunch of handler in the gui). In order to do
that I used a type inherited with no addition, just to understand that that
field is the path to an Image:
class Image(String): pass
clearly another alternative would be to use info={ 'image': true} or
similar. Is there some caveat that would make one preferred over the other?
TIA
sandro
*:-)
--
Sandro Dentella *:-)
http://sqlkit.argolinux.org SQLkit home page - PyGTK/python/sqlalchemy
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