On May 15, 2008, at 3:23 PM, Chris Guin wrote:
> My goal is to have a one-to-many relation defined using the same
> name as the foreign key column underneath. So that, if my
> "Detection" table has a foreignkey column named "sensor," the
> following mappers should work, I think:
allow_column_override is not used for this, its used to entirely
obliterate the knowledge of the underlying Column so that you can
place a relation() there instead. Its also deprecated since the same
effect can be acheived with "exclude_columns" (thanks for reminding me
so i can remove it from 0.5).
Since you dont want to obliterate the column and you actually need it,
do this:
mapper(Class, mytable, properties={
'_actual_foreign_key_column' : mytable.c.sensor,
'sensor':relation(Sensor)
})
>
>
> mapper(Sensor, sensor)
> detectionmapper = mapper(Detection, detection,
> allow_column_override= True , properties={
> 'sensor' : relation(Sensor),
> })
>
> I'm getting the following exception, however, when I actually create
> a Detection with a Sensor and try to flush the session:
>
> Traceback (most recent call last):
> File "<console>", line 1, in <module>
> File "c:\python25\lib\site-packages\SQLAlchemy-0.4.5-py2.5.egg
> \sqlalchemy\orm\scoping.py", line 98, in do
> return getattr(self.registry(), name)(*args, **kwargs)
> File "c:\python25\lib\site-packages\SQLAlchemy-0.4.5-py2.5.egg
> \sqlalchemy\orm\session.py", line 757, in flush
> self.uow.flush(self, objects)
> File "c:\python25\lib\site-packages\SQLAlchemy-0.4.5-py2.5.egg
> \sqlalchemy\orm\unitofwork.py", line 233, in flush
> flush_context.execute()
> File "c:\python25\lib\site-packages\SQLAlchemy-0.4.5-py2.5.egg
> \sqlalchemy\orm\unitofwork.py", line 445, in execute
> UOWExecutor().execute(self, tasks)
> File "c:\python25\lib\site-packages\SQLAlchemy-0.4.5-py2.5.egg
> \sqlalchemy\orm\unitofwork.py", line 930, in execute
> self.execute_save_steps(trans, task)
> File "c:\python25\lib\site-packages\SQLAlchemy-0.4.5-py2.5.egg
> \sqlalchemy\orm\unitofwork.py", line 948, in execute_save_steps
> self.execute_dependencies(trans, task, False)
> File "c:\python25\lib\site-packages\SQLAlchemy-0.4.5-py2.5.egg
> \sqlalchemy\orm\unitofwork.py", line 959, in execute_dependencies
> self.execute_dependency(trans, dep, False)
> File "c:\python25\lib\site-packages\SQLAlchemy-0.4.5-py2.5.egg
> \sqlalchemy\orm\unitofwork.py", line 942, in execute_dependency
> dep.execute(trans, isdelete)
> File "c:\python25\lib\site-packages\SQLAlchemy-0.4.5-py2.5.egg
> \sqlalchemy\orm\unitofwork.py", line 895, in execute
> self.processor.process_dependencies(self.targettask, [elem.state
> for elem in self.targettask.polymorphic_tosave_elements if elem
> .state is not None], trans, delete=False)
> File "c:\python25\lib\site-packages\SQLAlchemy-0.4.5-py2.5.egg
> \sqlalchemy\orm\dependency.py", line 332, in process_dependencies
> self._synchronize(state, child, None, False, uowcommit)
> File "c:\python25\lib\site-packages\SQLAlchemy-0.4.5-py2.5.egg
> \sqlalchemy\orm\dependency.py", line 374, in _synchronize
> sync.populate(child, self.mapper, state, self.parent,
> self.prop.synchronize_pairs)
> File "c:\python25\lib\site-packages\SQLAlchemy-0.4.5-py2.5.egg
> \sqlalchemy\orm\sync.py", line 27, in populate
> self._raise_col_to_prop(True, source_mapper, l, dest_mapper, r)
> NameError: global name 'self' is not defined
>
>
> I am still using SQLAlchemy 0.4.5.
>
> Thanks for any help!
> Chris
> >
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