I'm attempting to a sort of complex relationship filter/sort operation. I
need to filter results by the id of a parent relationship, and then sort a
nested relationship by one of its attributes
class Parent(Base):
__tablename__ = 'parent'
id = Column(types.Integer, primary_key=True, autoincrement=True)
name = Column(types.Unicode, nullable=False)
class ParentFeature(Base):
__tablename__ = 'parent_feature'
id = Column(types.Integer, primary_key=True, autoincrement=True)
parent_id = Column(ForeignKey('parent.id', ondelete='CASCADE'), nullable
=False, index=True)
parent = relationship('Parent')
unordered_things = relationship('Thing', secondary=
'parent_feature_thing')
things = relationship('Thing', secondary='parent_feature_thing',
order_by=Thing.name, viewonly=True)
class ParentFeatureThingPivot(Base):
__tablename__ = 'parent_feature_thing'
parent_feature_id = Column(ForeignKey('parent_feature.id', ondelete=
'CASCADE'), primary_key=True)
thing_id = Column(ForeignKey('thing_id.id', ondelete='CASCADE'),
primary_key=True)
class Thing(Base):
__tablename__ = 'thing'
id = Column(types.Integer, primary_key=True, autoincrement=True)
name = Column(types.Unicode, nullable=False)
Ideally on ParentFeature I would only need "things" and not
"unordered_things", but sometimes I query
directly against Parent, in which case it should always order_by ascending.
Anyways that works.
The actual issue, is that sometimes I need to be able to conditionally
order "things" on queries against
ParentFeature ascending or descending, and apparently(?) I can't use the
"things" relationship because
it is undconditionally applied to uses of that relationship
The query that I think should be working, but is not is like this:
direction = desc # or asc
result = (
pg.query(ParentFeature)
.join(ParentFeature.parent, ParentFeature.unordered_shows)
.options(
joinedload(ParentFeature.parent),
joinedload(ParentFeature.unordered_shows),
)
.filter(Parent.id == 3)
.order_by(direction(Thing.name))
)
except it still orders the final query ascending (or unordered? but
definitely not descending)
any ideas?
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