Awesome.
Does that mean the sqlalchemy example is wrong. It currently has:
if callable(value):
value = value()
Should it be something like that?
if value == None and bind.callable !=
None:
| verificationTokenExpiry = Column(String)
value = bind.callable()
Thank you so much for the quick response.
Arthur
On Jun 24, 10:05 am, Michael Bayer <[email protected]> wrote:
> On Jun 24, 2011, at 12:49 PM, Arthur Kopatsy wrote:
>
>
>
>
>
>
>
>
>
> > Hi,
>
> > I am trying to write a proper query_chooser method for our user based
> > sharding. To do so, I need to be able to query the value of the
> > query's criterions.
>
> > I have the following model:
> > class User(object):
> > id = Column(Integer, primary_key=True)
> > ...
>
> > class Subscription(object):
> > id = Column(Integer, primary_key=True)
> > producerId = Column(Integer, ForeignKey('User.id'))
> > consumerId = Column(Integer) # No foreign key because sharded on
> > producerId
> > producer = relationship('User', backref='subscriptions')
>
> > In my query_chooser, I am using the code from the attribute_sharding
> > example and try to find out the value of producerId if there is such a
> > criterion.
>
> > Given an existing myUser instance and a session, I see two different
> > behaviors:
>
> > 1. session.query(Subscription).filter(Subscription.producerId ==
> > myUser.id).all()
>
> > I will get a proper value for producerId in the dictionary of bound
> > parameters so I can find out the shard, no problem.
>
> > SELECT "InboundSubscription".s9id AS "InboundSubscription_s9id",
> > "InboundSubscription".active AS "InboundSubscription_active",
> > "InboundSubscription"."createdAt" AS "InboundSubscription_createdAt",
> > "InboundSubscription"."updatedAt" AS "InboundSubscription_updatedAt",
> > "InboundSubscription"."followerId" AS
> > "InboundSubscription_followerId", "InboundSubscription"."producerId"
> > AS "InboundSubscription_producerId", "InboundSubscription".status AS
> > "InboundSubscription_status", "InboundSubscription".suspended AS
> > "InboundSubscription_suspended"
> > FROM "InboundSubscription"
> > WHERE "InboundSubscription"."producerId" = :producerId_1
>
> > 2. myUser.subscriptions
>
> > I get a None value for the anonymous parameter which prevents me from
> > picking a shard.
>
> > SELECT "InboundSubscription".s9id AS "InboundSubscription_s9id",
> > "InboundSubscription".active AS "InboundSubscription_active",
> > "InboundSubscription"."createdAt" AS "InboundSubscription_createdAt",
> > "InboundSubscription"."updatedAt" AS "InboundSubscription_updatedAt",
> > "InboundSubscription"."followerId" AS
> > "InboundSubscription_followerId", "InboundSubscription"."producerId"
> > AS "InboundSubscription_producerId", "InboundSubscription".status AS
> > "InboundSubscription_status", "InboundSubscription".suspended AS
> > "InboundSubscription_suspended"
> > FROM "InboundSubscription"
> > WHERE :param_1 = "InboundSubscription"."producerId"
>
> > When is this value populated? How can I access it in query_chooser?
>
> The bindparam() object should have a "callable" attribute - call that to get
> the value. These values are late-bound when using lazyloading.
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