Kalium wrote:
>
> Hi,
> Just wondering if there is an easy way to determine what tables are
> joined in a query?
>
> I'm doing something like this
>
> query = session.query(System, dynamic_obj).select_from(self.j)
>
> Where dynamic_obj could be any mapped object and self.j represents a
> join produced by the sqlalchemy.schema.Table.join() function. I'd like
> to know if the table represented by dynamic_obj is already in the
> self.j
>
> I could of course do this programmatically outside of sqla, but it
> would be nice if sqla could tell me this.
here's how to do it like a pro
from sqlalchemy.sql import visitors
t1 = set()
visitors.traverse(
object_mapper(dynamic_obj).mapped_table,
{},
{'table':t1.add}
)
t2 = set()
visitors.traverse(self.j, {}, {'table':t2.add})
tables_that_are_in_both = t1.intersection(t2)
there's also a function sqlalchemy.sql.util.find_tables(expr) that does
the "visitors.traverse" thing for you.
>
> Cheers
>
> >
>
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