[sqlalchemy] Can we use dates to define a relation with the mapper ?
Hi,
I have this mapper defined:
mapper(Resource, resource_table,
properties = {'type' : relation(ResourceType,lazy = False),
'groups' : relation(Group, secondary =
model.tables['resource_group'], backref = 'resources'),
'parent' : relation(Relation, uselist=False, primaryjoin =
and_(relation_table.c.res_id == resource_table.c.res_id,
relation_table.c.end_date datetime.now())),
'children' : relation(Relation, primaryjoin =
and_(relation_table.c.parent_id == resource_table.c.res_id,
relation_table.c.end_date func.now()))})
But for some reason, if I create a new row in the relation table and
change the end_date of the old row in the relation to an old date, the
property parent is not updated.
Also if a reload the resource row, the old relation with the old date
is displayed, so I am pretty sure it has to do with the date
comparison in the mapper.
If I replace the end_date by a flag column string or integer and do a
comparison on the flag I get the proper behaviour, but I do want to
use dates.
Any help is welcome.
Thanks,
Richard Lopes
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Re: [sqlalchemy] Can we use dates to define a relation with the mapper ?
Hello,
On Mar 4, 2010, at 10:50 PM, Richard Lopes wrote:
Hi,
I have this mapper defined:
mapper(Resource, resource_table,
properties = {'type' : relation(ResourceType,lazy = False),
'groups' : relation(Group, secondary =
model.tables['resource_group'], backref = 'resources'),
'parent' : relation(Relation, uselist=False, primaryjoin =
and_(relation_table.c.res_id == resource_table.c.res_id,
relation_table.c.end_date datetime.now())),
'children' : relation(Relation, primaryjoin =
and_(relation_table.c.parent_id == resource_table.c.res_id,
relation_table.c.end_date func.now()))})
But for some reason, if I create a new row in the relation table and
change the end_date of the old row in the relation to an old date, the
property parent is not updated.
Also if a reload the resource row, the old relation with the old date
is displayed, so I am pretty sure it has to do with the date
comparison in the mapper.
If I replace the end_date by a flag column string or integer and do a
comparison on the flag I get the proper behaviour, but I do want to
use dates.
I imagine you're getting bitten because your datetime.now() is getting
evaluated at compile time. You might need to make it a callable. That said I'm
unsure about whether or not a callable will work with SQLAlchemy. I might be
able to write a test case tomorrow.
Michael
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Re: [sqlalchemy] Can we use dates to define a relation with the mapper ?
Hi,
Thanks for the help but I think I got it working.
Look here:
http://stackoverflow.com/questions/2384438/sqlalchemy-can-we-use-date-comparison-in-relation-definition
Cheers,
Richard
2010/3/5 Michael Trier mtr...@gmail.com
Hello,
On Mar 4, 2010, at 10:50 PM, Richard Lopes wrote:
Hi,
I have this mapper defined:
mapper(Resource, resource_table,
properties = {'type' : relation(ResourceType,lazy = False),
'groups' : relation(Group, secondary =
model.tables['resource_group'], backref = 'resources'),
'parent' : relation(Relation, uselist=False, primaryjoin =
and_(relation_table.c.res_id == resource_table.c.res_id,
relation_table.c.end_date datetime.now())),
'children' : relation(Relation, primaryjoin =
and_(relation_table.c.parent_id == resource_table.c.res_id,
relation_table.c.end_date func.now()))})
But for some reason, if I create a new row in the relation table and
change the end_date of the old row in the relation to an old date, the
property parent is not updated.
Also if a reload the resource row, the old relation with the old date
is displayed, so I am pretty sure it has to do with the date
comparison in the mapper.
If I replace the end_date by a flag column string or integer and do a
comparison on the flag I get the proper behaviour, but I do want to
use dates.
I imagine you're getting bitten because your datetime.now() is getting
evaluated at compile time. You might need to make it a callable. That said
I'm unsure about whether or not a callable will work with SQLAlchemy. I
might be able to write a test case tomorrow.
Michael
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R. LOPES
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