thanks. i'll give it a shot.
On Jan 17, 10:43 am, Michael Bayer <mike...@zzzcomputing.com> wrote:
> On Jan 17, 2009, at 4:07 AM, n00b wrote:
>
>
>
>
>
> > greetings,
>
> > i'm batch processing xml documents to mysql using SA 0.5, ORM.
>
> > data extracted from xml docs may be new or an update in form of a
> > replacement of
> > the existing object (record). (one of the columns, product_id, is
> > unique=True). Hence,
> > SA throws, as expected, an IntegrityError (1062, duplicate Entry) when
> > i'm trying to commit the revised object via session.add(obj),
> > session.commit().
>
> > given the xml volume at hand, i thought i could use session.merge
> > rather than query every time for existence. alas, no go. get the same
> > 1062 exception. obviously, i don't understand the session merge.
>
> > in fact, even if i query for the existence, then try and assign the
> > new object to the existing object (old_obj = session.query(OBJ).filter
> > (OBJ.product_id == new_obj.product.id).one(), old_obj = new_obj,
> > session.add(old_obj), session.commit()), i get the dreaded 1062.
>
> > any insights/suggestions?
>
> you're on the right track, except that merge() is basing its "do i
> update an existing object" based on primary keys, not just unique
> constraints. you'd have to merge() objects that match up to those you
> want to update based on primary key. if your tables don't look like
> that, you can still configure the mapper() to consider any arbitrary
> set of columns as primary key columns using the "primary_key" argument.
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