We have tried suggested, but: field 'modified' exists in both parent
and child tables, when we redefined property 'modified' in mapper with
something like this:
mapper(Child, child_table, properties={'modified' =
child_table.c.modified, ...}), modified field still returned value
from parent's table.
We also tried to add property to class like this:
class Parent(object) :
table = None
...
def _fieldFromQuery(self, field):
if not self.table:
return None
return Session.object_session(self).execute(select([getattr
(self.table.c, field)]).where(self.table.c.id==self.id)).scalar()
def _modified(self):
return self._fieldFromQuery("modified")
def _modified_by(self):
return self._fieldFromQuery("modified_by")
modified = property(_modified)
modified_by = property(_modified_by)
where self.table is assigned just before mapper is created.
Mapper itself again redefined attribute 'modified' and 'modified_by'
so we were back to starting problem.
On Oct 29, 3:56 pm, "Michael Bayer" <mike...@zzzcomputing.com> wrote:
> bojanb wrote:
>
> > Hi,
>
> > Can I have identical column names in both parent and child classes
> > that are part of a joined-table inheritance? These are simply created,
> > created_by, modified, modified_by columns that are populated by
> > defaults defined for them (ie. default, server_default, onupdate).
>
> > The values are written to the database correctly, but I have a problem
> > reading them because parent's column values override child values. So,
> > if the parent has null values for modified, modified_by and the child
> > some actual values, ORM returns None for child.modified and
> > child.modified_by.
>
> use the "properties" dictionary to mapper to redefine the names. or the
> declarative equivalent.
> seehttp://www.sqlalchemy.org/docs/05/mappers.html#customizing-column-pro...
>
>
>
> > Suggestions?
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