Multiple LEFTJOINOn queries seem to work if all classes subclass
SQLObject, but not if they subclass a subclass of
InheritableSQLObject. This is what I mean:
################################################################
class zoo( SQLObject ):
name = StringCol( )
cages = MultipleJoin( 'cage' )
class cage( SQLObject ):
name = StringCol( )
animals = MultipleJoin( 'animal' )
zoo = ForeignKey( 'zoo' )
class animal( SQLObject ):
name = StringCol( )
cage = ForeignKey( 'cage' )
################################################################
So there are zoos, each zoo has a number of cages and each cage has a
number of animals. The following query selects the total number of
animals in a given zoo:
################################################################
joins = [ ]
joins.append( LEFTJOINOn( None, cage, animal.q.cageID==cage.q.id ) )
joins.append( LEFTJOINOn( None, zoo, cage.q.zooID==zoo.q.id ) )
print animal.select( zoo.q.name=='myzoo', join=joins ).count( )
################################################################
This is all fine, but if the model is changed slightly to use inheritance:
################################################################
class named( InheritableSQLObject ):
name = StringCol( )
class zoo( named ):
cages = MultipleJoin( 'cage' )
class cage( named ):
animals = MultipleJoin( 'animal' )
zoo = ForeignKey( 'zoo' )
class animal( named ):
cage = ForeignKey( 'cage' )
################################################################
then the exact same query stops working. Why is that? If it is a
feature and not a bug, what should be the correct query for the
getting the total number of animals?
Daniel
python 2.5, SQLObject-0.10dev_r2660, sqlite.
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