If I understand:
for row in db(db.link_table.table1==r.id)
(db.table2.id==db.linked_table.table2).select(db.table2.id,db.table2.other):
print row.id, row.other
if no double links else
sub=db(db.link_table.table1==r.id)._select(db.linked_table.table2)
for row in
db(db.table2.id.belongs(sub)).select(db.table2.id,db.table2.other):
print row.id, row.other
linked_view = db(db.table1.id == db.link_table.table1) & (db.table2.id
> == db.linked_table.table2))
>
> for row in linked_view(db.table1.id == r.id).select([fields from
> table2 I want])
On 29 Giu, 17:54, Al <rayalans...@yahoo.com> wrote:
> Given a many-to-many relationship between table1 and table2 and a row
> in table1, I am trying to figure out the fastest way to select all the
> rows in table2 that are associated with the row. (I'm still trying to
> pick up web2py, so thanks for everyone's patience if I've missed the
> blatently obvious.)
>
> From the web2py book documentation, the best I can figure out is
> something like this:
> db.define_table('link_table',
> Field('table1', db.table1),
> Field('table2', db.table2)
> )
>
> # Pick the row from table 1
> r = db(db.table1.name == "Example").select()[0]
>
> linked_view = db(db.table1.id == db.link_table.table1) & (db.table2.id
> == db.linked_table.table2))
>
> for row in linked_view(db.table1.id == r.id).select([fields from
> table2 I want])
> # Do something clever for the matching rows I've found
> pass
>
> But I keep thinking there ought to be something cleverer that I can
> do, especially given that r has a set containing the rows of
> link_table that contain the entries of table2 that I want. But I can't
> figure out how to leverage that set into a shorter query.
>
> Thanks,
> Al
