I have a simple many to many relationship between two objects: Task and
Note, where notes are ordered by a timestamp column most recent first.
About 90% of the time what I really want to do is eagerload only the
most recent note, is there a way to do this in the mapper?
My mapper for Task looks like this:
mapper(Task,task_table, properties={
'Notes':relation(Note,secondary=note_task_table,
order_by=note_table.c.updated.desc(), backref='Tasks'),
'State':relation(TaskState),
'Group':relation(Group, lazy=True)},
save_on_init=False)
Usually my code ends up looking like:
>>>
tasks=session.query(Task).filter(Task.assigned_to=='dgardner').options(eagerload(Task.Notes)).all()
>>> for task in tasks:
... if len(task.Notes):
... latest_note=task.Notes[0]
--
David Gardner
Pipeline Tools Programmer, "Sid the Science Kid"
Jim Henson Creature Shop
dgard...@creatureshop.com
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