IndirectReferenceSet.find().something() produces non-working queries

Setting database.DEBUG=True I get (sqlite backend, fails the same way with mysql, too):

SELECT foo.id, foo.title FROM foo WHERE foo.id = ? LIMIT 1 (20,)
SELECT bar.foo_id, bar.id, bar.title FROM bar WHERE bar.id = ? LIMIT 1 (300,)
INSERT INTO link (bar_id, foo_id) VALUES (?, ?) (300, 20)
UPDATE bar SET title=? WHERE link.foo_id = ? AND bar.id = link.bar_id (u'hoho', 20)

doing a:

   foo.bars.find().remove()

fails too.

For databases like PostgreSQL (at least), we should be able to generate working queries.

For foo.bars.find().set(title=u"hoho"), the following is valid in PG:

    UPDATE bar SET title='hoho' FROM link
      WHERE link.foo_id = 20 AND bar.id = link.bar_id;

Similarly, for foo.bars.find().remove(), the following works:

    DELETE FROM bar USING link
      WHERE link.foo_id = 20 AND bar.id = link.bar_id;

It looks like MySQL supports "DELETE ... USING", but has a different syntax for the UPDATE:

    UPDATE bar, link SET bar.title='hoho' FROM link
      WHERE link.foo_id = 20 AND bar.id = link.bar_id;

It doesn't look like SQLite supports this type of feature for either UPDATE or DELETE. So it will probably be necessary to do per-backend statement compilation to solve this bug.

Oops. The MySQL example should have been:

    UPDATE bar, link SET bar.title='hoho'
      WHERE link.foo_id = 20 AND bar.id = link.bar_id;