I have a users table, with a lazy=False, innerjoin=True relation to the
preferences table
(these could probably be the same table but they are separate for
historical reasons).
One of the gotchas that I am running into is when I do an outerjoin on
to the user's table,
it effectively becomes a join.
r = session.query(Report).options(eagerload(Report.Users)).get(report_name)
returns 0 rows when report_name doesn't have any subscribed users I can
and do work around this
by assing in a options(lazyload('Users.Preferences')) to the query.
The generated SQL looks like:
SELECT <bunch of columns>
FROM report
LEFT OUTER JOIN user_report AS user_report_1 ON report.name =
user_report_1.report
LEFT OUTER JOIN users AS users_1 ON users_1.user_id = user_report_1."user"
JOIN user_prefs AS user_prefs_1 ON users_1.user_id = user_prefs_1."user"
WHERE report.name = %(param_1)s
However I wonder if it is feasible for SQLAlchemy to detect this and
generate this instead:
SELECT <bunch of columns>
FROM report
LEFT OUTER JOIN user_report AS user_report_1 ON report.name =
user_report_1.report
LEFT OUTER JOIN (users JOIN user_prefs AS user_prefs_1 ON users.user_id
= user_prefs_1."user" )
AS users_1 ON users_1.user_id = user_report_1."user"
Like I mentioned, I already have a work-around for this, and I realize
this is a function of the way I
defined my mappers.
--
David Gardner
Pipeline Tools Programmer
Jim Henson Creature Shop
[email protected]
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