Thanks for the insight Michael -- some records in the content table
had a 'type' of one of the subclasses, but not a record in the
corresponding subclass table -- works like a charm once I insert
records for everything in the subclass tables.
Matt
On Nov 18, 7:58 pm, Michael Bayer <[EMAIL PROTECTED]> wrote:
> On Nov 18, 2007, at 10:15 PM, Matt wrote:
>
>
>
>
>
> > I have some classes that inherit from one another, here are the
> > mappers:
>
> > mapper(Content, content, polymorphic_on=content.c.type,
> > polymorphic_identity='content')
> > mapper(TvContent, content_tv_metadata, inherits=Content,
> > polymorphic_identity='tv show')
> > mapper(SoftwareContent, content_software_metadata, inherits=Content,
> > polymorphic_identity='software')
> > mapper(MusicContent, content_music_metadata, inherits=Content,
> > polymorphic_identity='music')
> > mapper(MovieContent, content_movie_metadata, inherits=Content,
> > polymorphic_identity='movie')
>
> > And the error I'm getting?
>
> > Traceback (most recent call last):
> > File "./test_sahara_content.py", line 19, in ?
> > x = q.get(16634)
> > File "/Library/Frameworks/Python.framework/Versions/2.4/lib/
> > python2.4/site-packages/SQLAlchemy-0.4.1-py2.4.egg/sqlalchemy/orm/
> > query.py", line 96, in get
> > return self._get(key, ident, **kwargs)
> > File "/Library/Frameworks/Python.framework/Versions/2.4/lib/
> > python2.4/site-packages/SQLAlchemy-0.4.1-py2.4.egg/sqlalchemy/orm/
> > query.py", line 778, in _get
> > return q.all()[0]
> > File "/Library/Frameworks/Python.framework/Versions/2.4/lib/
> > python2.4/site-packages/SQLAlchemy-0.4.1-py2.4.egg/sqlalchemy/orm/
> > query.py", line 608, in all
> > return list(self)
> > File "/Library/Frameworks/Python.framework/Versions/2.4/lib/
> > python2.4/site-packages/SQLAlchemy-0.4.1-py2.4.egg/sqlalchemy/orm/
> > query.py", line 656, in __iter__
> > return self._execute_and_instances(context)
> > File "/Library/Frameworks/Python.framework/Versions/2.4/lib/
> > python2.4/site-packages/SQLAlchemy-0.4.1-py2.4.egg/sqlalchemy/orm/
> > query.py", line 661, in _execute_and_instances
> > return iter(self.instances(result, querycontext=querycontext))
> > File "/Library/Frameworks/Python.framework/Versions/2.4/lib/
> > python2.4/site-packages/SQLAlchemy-0.4.1-py2.4.egg/sqlalchemy/orm/
> > query.py", line 727, in instances
> > context.attributes.get(('populating_mapper', id(instance)),
> > object_mapper(instance))._post_instance(context, instance)
> > File "/Library/Frameworks/Python.framework/Versions/2.4/lib/
> > python2.4/site-packages/SQLAlchemy-0.4.1-py2.4.egg/sqlalchemy/orm/
> > mapper.py", line 1549, in _post_instance
> > p(instance)
> > File "/Library/Frameworks/Python.framework/Versions/2.4/lib/
> > python2.4/site-packages/SQLAlchemy-0.4.1-py2.4.egg/sqlalchemy/orm/
> > mapper.py", line 1568, in post_execute
> > self.populate_instance(selectcontext, instance, row, isnew=False,
> > instancekey=identitykey, ispostselect=True)
> > File "/Library/Frameworks/Python.framework/Versions/2.4/lib/
> > python2.4/site-packages/SQLAlchemy-0.4.1-py2.4.egg/sqlalchemy/orm/
> > mapper.py", line 1519, in populate_instance
> > (newpop, existingpop, post_proc) =
> > selectcontext.exec_with_path(self, prop.key,
> > prop.create_row_processor, selectcontext, self, row)
> > File "/Library/Frameworks/Python.framework/Versions/2.4/lib/
> > python2.4/site-packages/SQLAlchemy-0.4.1-py2.4.egg/sqlalchemy/orm/
> > query.py", line 1243, in exec_with_path
> > return func(*args, **kwargs)
> > File "/Library/Frameworks/Python.framework/Versions/2.4/lib/
> > python2.4/site-packages/SQLAlchemy-0.4.1-py2.4.egg/sqlalchemy/orm/
> > interfaces.py", line 487, in create_row_processor
> > return
> > self
> > ._get_context_strategy
> > (selectcontext).create_row_processor(selectcontext,
> > mapper, row)
> > File "/Library/Frameworks/Python.framework/Versions/2.4/lib/
> > python2.4/site-packages/SQLAlchemy-0.4.1-py2.4.egg/sqlalchemy/orm/
> > strategies.py", line 75, in create_row_processor
> > elif self.columns[0] in row:
> > TypeError: iterable argument required
>
> > Any ideas? This is using 0.4.1
>
> my idea is that the mapper is trying to load the row for a subclass
> table, such as content_software_metadata, and its getting back None
> for the row....which should ideally raise an assertion error. but its
> not so its going much deeper before it craps out. As to why the row
> is None, from what you've shown ive no idea (unless you've manipulated
> those tables externally to the ORM, that would do it). Im looking at
> unit tests which have essentially the exact same code. So, youd have
> to tell me if this error occurs with 0.4.0 as well, and you also need
> to send me the full structure of your tables and the code that exactly
> produces the error. if its actualy a bug which was introduced in
> 0.4.1, you can look forward to 0.4.2 by tomorrow at the latest.
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