[sqlalchemy] Python 3.4 Enum type
Since Python 3.4 is adding support for enums to the standard library, I wrote a TypeDecorator for it: import sqlalchemy.types as types class PythonEnum(types.TypeDecorator): impl = types.Enum def __init__(self, enum_class, **kw): super().__init__(*(m.name for m in enum_class), **kw) self._enum_class = enum_class def process_bind_param(self, value, dialect): return value.name def process_result_value(self, value, dialect): return self._enum_class[value] @property def python_type(self): return self._enum_class Comments welcome. Is this something that should be added to sqlalchemy? -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/groups/opt_out.
Re: [sqlalchemy] Python 3.4 Enum type
there's a lot of flavors of python enum and I recall the standard library one rubs me the wrong way a bit. I'd prefer for sqlalchemy.Enum to have some easy way to accommodate any Python-side enum using some kind of convention, obviously one that's compat with the std lib enum. On Aug 6, 2013, at 5:12 PM, Ian Kelly ian.g.ke...@gmail.com wrote: Since Python 3.4 is adding support for enums to the standard library, I wrote a TypeDecorator for it: import sqlalchemy.types as types class PythonEnum(types.TypeDecorator): impl = types.Enum def __init__(self, enum_class, **kw): super().__init__(*(m.name for m in enum_class), **kw) self._enum_class = enum_class def process_bind_param(self, value, dialect): return value.name def process_result_value(self, value, dialect): return self._enum_class[value] @property def python_type(self): return self._enum_class Comments welcome. Is this something that should be added to sqlalchemy? -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/groups/opt_out. signature.asc Description: Message signed with OpenPGP using GPGMail
[sqlalchemy] Association Proxy question ( or other ORM feature )
I have three tables that are structured somewhat like this: Document * id * all_images = sa.orm.relationship(Document2Image) Image * id * all_documents = sa.orm.relationship(Document2Image) Document2Image * id * document_id * image_id * image_type_id * document = sa.orm.relationship(Document) * image = sa.orm.relationship(Image) is there a convenient way to set up a relationship on Document where it maps to Document2Image with a specific Document2Image.image_type_id ? I believe I want a variant of the Association Proxy [ http://docs.sqlalchemy.org/en/rel_0_8/orm/extensions/associationproxy.html ] that was listed in Relationships - Association Object [ http://docs.sqlalchemy.org/en/rel_0_8/orm/relationships.html#association-object ] I just can't wrap my head around this. What I'd like to have is something like : Document * id * all_images = sa.orm.relationship(Document2Image) * header_image = sa.orm.relationship( Image , filter( Image.image_type_id == 1 , Image.id == Document2Image.image_id , Document2Image.document_id == Document.id ) this way i can just write out : document.header_image and either see 'None' or the 'Image' object. if it matters, i'm only concerned with reads right now. -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/groups/opt_out.
Re: [sqlalchemy] Association Proxy question ( or other ORM feature )
On Aug 6, 2013, at 6:23 PM, Jonathan Vanasco jonat...@findmeon.com wrote: I have three tables that are structured somewhat like this: Document * id * all_images = sa.orm.relationship(Document2Image) Image * id * all_documents = sa.orm.relationship(Document2Image) Document2Image * id * document_id * image_id * image_type_id * document = sa.orm.relationship(Document) * image = sa.orm.relationship(Image) is there a convenient way to set up a relationship on Document where it maps to Document2Image with a specific Document2Image.image_type_id ? I believe I want a variant of the Association Proxy [ http://docs.sqlalchemy.org/en/rel_0_8/orm/extensions/associationproxy.html ] that was listed in Relationships - Association Object [ http://docs.sqlalchemy.org/en/rel_0_8/orm/relationships.html#association-object ] you can build a relationship from Document to Document2Image using a custom primaryjoin, then relationship to Image, then association proxy. Or, you can produce a select() of what rows you want from Document2Image, then make that as the secondary argument between a single relationship on Document-Image. If OTOH you want a join condition that uses columns from Document2Image and Image at the same time, sometimes you can make a select() of those two things, then create a non primary mapper to Image using that select() as the base, then Document gets a relationship referring to that non-primary mapper. signature.asc Description: Message signed with OpenPGP using GPGMail
[sqlalchemy] notin_ passed empty sequence with unexpected substitution
Hi, I'm running: selected_eventids = [] selected_event = self.session.query(Master_Simulation_Event).filter(Master_Simulation_Event.cumulative_probability = selection_percentile, Master_Simulation_Event.event_id.notin_(selected_eventids) ).\ order_by(Master_Simulation_Event.cumulative_probability - selection_percentile).first() And it generates: 2013-08-06 18:03:43,196 INFO sqlalchemy.engine.base.Engine SELECT TOP 1 master_simulation_events.id AS master_simulation_events_id, master_simulation_events.event_id AS master_simulation_events_event_id, master_simulation_events.rate AS master_simulation_events_rate, master_simulation_events.sample_probability AS master_simulation_events_sample_probability, master_simulation_events.cumulative_probability AS master_simulation_events_cumulative_probability FROM master_simulation_events WHERE master_simulation_events.cumulative_probability = ? AND master_simulation_events.event_id != master_simulation_events.event_id ORDER BY master_simulation_events.cumulative_probability - ? 2013-08-06 18:03:43,196 INFO sqlalchemy.engine.base.Engine (0.19528160149168805, 0.19528160149168805) The important part is the notin_([]) is translated to: master_simulation_events.event_id != master_simulation_events.event_id I recieve the following warning: C:\Python27\lib\site-packages\sqlalchemy\sql\expression.py:1982: SAWarning: The IN-predicate on master_simulation_events.event_id was invoked with an empty sequence. This results in a contradiction, which nonetheless can be expensive to evaluate. Consider alternative strategies for improved performance. return o[0](self, self.expr, op, *(other + o[1:]), **kwargs) While it doesn't make a lot of sense to pass an empty list to an in_ clause I think passing an emtpy list list to notin_ clause is OK and it shouldn't be replaced. Is this a bug? ~Victor -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/groups/opt_out.
