Thanks for taking a peek.
Interesting, it does indeed fix the issue to use labels. Now I have
another issue though, I have a case statement in my select which I was
specifying like this:
select ( ['case when .... yada yada yada end as something' ] ......
If use_labels = True, then the query breaks because the generated sql
has two as label parts two it.
if I delete the "as something" part, I think don't know
programatically what the label is though. I need to know that because
I order by it.
Isn't there a way to find out a column label from a query?
-Dennis
On Feb 27, 12:47 pm, Michael Bayer <[EMAIL PROTECTED]> wrote:
> if you run it with full blown logging on, i.e.:
>
> import logging
> logging.basicConfig()
> logging.getLogger('sqlalchemy.engine').setLevel(logging.DEBUG)
> logging.getLogger('sqlalchemy.orm').setLevel(logging.DEBUG)
>
> the issue can be detected when you look at the mapper creating
> instance keys for "T" (although this is clearly not a novice issue):
>
> DEBUG:sqlalchemy.orm.mapper.Mapper:(T|ts) _instance(): identity key
> (<class '__main__.T'>, (1,), None) not in session[]
> DEBUG:sqlalchemy.orm.mapper.Mapper:(T|ts) _instance(): identity key
> (<class '__main__.T'>, (None,), None) not in session[]
> DEBUG:sqlalchemy.orm.mapper.Mapper:(T|ts) _instance(): identity key
> (<class '__main__.T'>, (3,), None) not in session[]
> DEBUG:sqlalchemy.orm.mapper.Mapper:(T|ts) _instance(): identity key
> (<class '__main__.T'>, (None,), None) not in session[]
> DEBUG:sqlalchemy.orm.mapper.Mapper:(T|ts) _instance(): identity key
> (<class '__main__.T'>, (5,), None) not in session[]
>
> so its not getting an identity key for every other row, which
> indicates its looking at the wrong column in the result set. (on
> each of those "None"s, its going to skip that entity) looking at the
> query:
>
> SELECT ts.id, ts.dat, other.ts_id, other.other_dat
> FROM ts LEFT OUTER JOIN other ON ts.id = other.ts_id
>
> we can see that "other" has a column called "ts_id", which looks
> exactly like the label that would be made for "id" in table "ts". so
> thats whats happening here. so throwing on a "use_labels=True" to
> the query (or changing the name of "ts_id") produces the query:
>
> SELECT ts.id AS ts_id, ts.dat AS ts_dat, other.ts_id AS other_ts_id,
> other.other_dat AS other_other_dat
> FROM ts LEFT OUTER JOIN other ON ts.id = other.ts_id
>
> that gives the correct results.
>
> not sure what SA can really do here to make this kind of issue easier
> to catch, since the resultproxy itself is where its looking for "col
> label, col name, ", etc. the generated labels are generally more
> accurate. i tried playing around with ResultProxy to make it detect
> an ambiguity of this nature, but i think it might not be possible
> unless more flags/switches get passed from the statement to the
> result (which id rather not do since it further marginalizes straight
> textual queries), since if the select statement uses table/col labels
> for each column, there still could be conflicts which dont matter,
> such as the column names the normal eager loader generates:
>
> 'ts_id', 'ts_dat', 'other_4966_ts_id', 'other_4966_other_dat',
>
> that result is from column "ts_id" attached to an Alias
> "other_4966". if we said "dont allow any Column to be found twice in
> the row", then that breaks (since it will match other_4966_ts_id on
> its _label, ts_id on its name).
>
> On Feb 27, 2007, at 12:09 PM, Dennis Muhlestein wrote:
>
> > from sqlalchemy import *
>
> > e=create_engine('sqlite://memory')
> > ts=Table('ts',e,
> > Column ( 'id',Integer,primary_key=True),
> > Column ( 'dat',Integer,nullable=False))
> > ts.create()
>
> > to_oneornone=Table('other',e,
> > Column ( 'ts_id', Integer,ForeignKey('ts.id'), primary_key=True,
> > nullable=False ),
> > Column ( 'other_dat', Integer, nullable=False ) )
> > to_oneornone.create()
>
> > class T(object): pass
> > T.mapper=mapper(T,ts)
>
> > class To(object):pass
> > To.mapper=mapper(To,to_oneornone,properties={'ts':relation
> > (T,backref=backref('other',uselist=False))})
>
> > s=create_session()
> > for x in range(10):
> > t=T()
> > t.dat=x
> > s.save(t)
>
> > if x % 2 == 0: # test every other T has an optional data
> > o=To()
> > o.other_dat=x
> > t.other=o
>
> > s.save(t)
> > s.flush()
>
> > s.clear()
>
> > somedata=s.query(T).options(eagerload('other')).select()
> > print 'Number results should be 10: ', len(somedata)
>
> > s.clear()
>
> > sel=select([ts,to_oneornone],
> > from_obj=[ts.outerjoin(to_oneornone)])
>
> > print "Raw select also is 10: " , len(sel.execute().fetchall() )
>
> > print "Instances should also be 10: ", len(s.query(T).options
> > (contains_eager('other')).instances(sel.execute()))
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"sqlalchemy" group.
To post to this group, send email to sqlalchemy@googlegroups.com
To unsubscribe from this group, send email to [EMAIL PROTECTED]
For more options, visit this group at
http://groups.google.com/group/sqlalchemy?hl=en
-~----------~----~----~----~------~----~------~--~---
