On May 12, 2008, at 1:48 PM, [EMAIL PROTECTED] wrote:
>
>>>> cls.query.left_bracket().filter_or(cls.y ==
>>>> 17).filter_or(cls.x==27).right_bracket()
>>>> is clearer than this:
>>>> cls.query.filter(or_(cls.y == 17, cls.x==27))
>>>
>>> it's not. it's not about replacing the or_. noone should use it
>>> that way...
>>>
>>> u have horses and owners with houses and hats.
>>> give me horses (whose owners have a hat of size 10 and color
>>> green) or (whose owners have a house of color red) or (have no
>>> tail)
>>
>> filter(or_(
>> horses.owners.any(hatsize=10, color='green'),
>> horses.owners.any(and_(owners.house_id==houses.house_id,
>> houses.color=='red')),
>> horses.tail == None
>> ))
>
> ahha, so thats how joins can go inside or_().
> isn't this (i guess it has subselects) more expensive than a single
> plain or/and clause?
if you wanted to spell it out with JOIN you can do that too -
house_owners = aliased(Owner)
hat_owners = aliased(Owner)
query(Horse).outerjoin((house_owners, 'owners'), 'houses').\
outerjoin((hat_owners, 'owners'), 'hats').\
filter(or_(
and_(Hat.size==10, Hat.color=='green'),
House.color=='red',
Horse.tail == None
))
im not sure but you might be also able to disable aliasing on House/
Hat if you said query.outerjoin('owners', (House, 'houses'),
aliased=True)...thats a little more experimental tho.
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