Re: [sqlalchemy] array_agg() in ORM entities (0.5.8)?
I was able to come up with a work-around, since this is part of a report, I was able to format the dates as strings the way I was planning to do in python anyways: qry=session.query(Task, func.cat(func.to_char(TaskHistory.updated,'MM/DD/YY HH:MI am'))) This works well for my needs (cat() isn't a standard Postgres aggregate, but instead something I wrote up in plpgsql). Michael Bayer wrote: oh. interesting problem, yeah. query is uniqing the values returned and assumes they are all hashable - it does this when any of the items in the row are full entities (i.e. your Task here). I don't know that there's a workaround for now other than using a TypeDecorator that turns the returned list into a tuple. -- David Gardner Pipeline Tools Programmer Jim Henson Creature Shop dgard...@creatureshop.com -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalch...@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
[sqlalchemy] array_agg() in ORM entities (0.5.8)?
I was trying to use the Postrges array_agg() aggregate function against a column on a related table. In this case I wanted a list of timestamps from a related table, but I get an error that the list type is unhashable. The SQL that SA generates is as expected, and if I replace func.array_agg with something that returns a hashable value like func.count() then it works as expected. Is this a requirement that entities must be hashable? If so can I write a TypeDecorator that implements __hash__? My code looks something like this: qry=session.query(Task, func.array_agg(TaskHistory.updated)) qry=qry.join(Task.History) qry=qry.filter(Task.priority5).filter(Task.state!='Approved') qry=qry.group_by(Task).order_by(Task.asset,Task.name) results=qry.all() --- TypeError Traceback (most recent call last) /users/dgardner/src/pcs/asset/farm/ipython console in module() /usr/lib/pymodules/python2.6/sqlalchemy/orm/query.pyc in all(self) 1265 1266 - 1267 return list(self) 1268 1269 @_generative(_no_clauseelement_condition) /usr/lib/pymodules/python2.6/sqlalchemy/orm/query.pyc in instances(self, cursor, _Query__context) 1426 1427 if filter: - 1428 rows = filter(rows) 1429 1430 if context.refresh_state and self._only_load_props and context.refresh_state in context.progress: /usr/lib/pymodules/python2.6/sqlalchemy/util.pyc in unique_list(seq, compare_with) 1087 def unique_list(seq, compare_with=set): 1088 seen = compare_with() - 1089 return [x for x in seq if x not in seen and not seen.add(x)] 1090 1091 class UniqueAppender(object): TypeError: unhashable type: 'list' -- David Gardner Pipeline Tools Programmer Jim Henson Creature Shop dgard...@creatureshop.com -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalch...@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
Re: [sqlalchemy] array_agg() in ORM entities (0.5.8)?
On Apr 1, 2010, at 7:45 PM, David Gardner wrote: I was trying to use the Postrges array_agg() aggregate function against a column on a related table. In this case I wanted a list of timestamps from a related table, but I get an error that the list type is unhashable. The SQL that SA generates is as expected, and if I replace func.array_agg with something that returns a hashable value like func.count() then it works as expected. Is this a requirement that entities must be hashable? If so can I write a TypeDecorator that implements __hash__? oh. interesting problem, yeah. query is uniqing the values returned and assumes they are all hashable - it does this when any of the items in the row are full entities (i.e. your Task here). I don't know that there's a workaround for now other than using a TypeDecorator that turns the returned list into a tuple. My code looks something like this: qry=session.query(Task, func.array_agg(TaskHistory.updated)) qry=qry.join(Task.History) qry=qry.filter(Task.priority5).filter(Task.state!='Approved') qry=qry.group_by(Task).order_by(Task.asset,Task.name) results=qry.all() --- TypeError Traceback (most recent call last) /users/dgardner/src/pcs/asset/farm/ipython console in module() /usr/lib/pymodules/python2.6/sqlalchemy/orm/query.pyc in all(self) 1265 1266 - 1267 return list(self) 1268 1269 @_generative(_no_clauseelement_condition) /usr/lib/pymodules/python2.6/sqlalchemy/orm/query.pyc in instances(self, cursor, _Query__context) 1426 1427 if filter: - 1428 rows = filter(rows) 1429 1430 if context.refresh_state and self._only_load_props and context.refresh_state in context.progress: /usr/lib/pymodules/python2.6/sqlalchemy/util.pyc in unique_list(seq, compare_with) 1087 def unique_list(seq, compare_with=set): 1088 seen = compare_with() - 1089 return [x for x in seq if x not in seen and not seen.add(x)] 1090 1091 class UniqueAppender(object): TypeError: unhashable type: 'list' -- David Gardner Pipeline Tools Programmer Jim Henson Creature Shop dgard...@creatureshop.com -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalch...@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en. -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalch...@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
