On Jun 17, 2013, at 08:58 , Chris Withers <ch...@simplistix.co.uk> wrote:
> Hi All,
>
> I seems to commonly need to do a query which should return zero or one mapped
> objects.
>
> .one() isn't what I want as no returned object is ok.
>
> .first() isn't what I want as if my query would return more than one object,
> I have the query wrong and so want an exception.
>
> Is there something already available that meets this need?
This will requrie you to run a query which limits the result to max 2 rows so
you can check if more than one result would be returned. I would just create a
simple wrapper function:
def one_optional(query):
rows = query.limit(2).all()
count = len(rows)
if count == 0:
return None
elif count == 1:
return rows[0]
else:
raise RuntimeError('More than one result found.')
Wichert.
--
You received this message because you are subscribed to the Google Groups
"sqlalchemy" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to sqlalchemy+unsubscr...@googlegroups.com.
To post to this group, send email to sqlalchemy@googlegroups.com.
Visit this group at http://groups.google.com/group/sqlalchemy.
For more options, visit https://groups.google.com/groups/opt_out.
