On Sep 19, 2011, at 10:37 AM, Moshe C. wrote:
> Hi,
> I have the following situation:
> There are two tables, A and B , both of which have an "id" column.
>
> In a certain part of the code I have an ORM query object.
> That query object is returned by some function and I have no apriori
> knowledge of its structure.
> I am assured, though that there will be an 'id' column. It might be a
> SELECT from A, a SELECT from B or a SELECT from A join B ON
> A.id=B.id.
>
> I would like to execute a query.values('id').
>
> This works for the first two cases but in the case of a join it
> complains because it does not know if I mean A.id or B.id.
> The thing is that I obviously do not care because they are both equal
> as a result of the join condition.
> I cannot select A.id or B.id because there is always a case of a query
> that does not have A or B.
>
> Is there a way to solve this elegantly? I.e. without having to inspect
> that structure of the query first.
Do a hasattr() on both A and B to see which one has "id". So a bit of
inspection but not much. Otherwise, the Query should be constructed such that
one of the attributes is definitely *named* "id" so that values('id') would
work. Using code like MySelectable.somecolumn.label('id') would ensure this.
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