Hi all,
Another patch; MySQL doesn't currently support correlated subqueries
in FROM clauses. This improves the error message you get in that
situation. (I didn't actually want or need a correlated subquery,
but I also spent quite some considerable time trying to work out what
was going on because MySQL threw a syntax error rather than
explaining that it didn't like correlated subqueries in the FROM part
of a SELECT.)
(Note: I have assumed that it's only possible to reach this code with
a subquery in the FROM clause or the WHERE clause... if it's also
possible to get here with a scalar or row subquery, then this code
isn't quite right.)
Kind regards,
Alastair.
Index: lib/sqlalchemy/sql.py
===================================================================
--- lib/sqlalchemy/sql.py (revision 926)
+++ lib/sqlalchemy/sql.py (working copy)
@@ -1246,6 +1246,8 @@
return
select.is_where = self.is_where
select.issubquery = True
+ if not (self.is_where or
select.engine.can_correlate_froms):
+ raise "The selected engine does not support
correlated subqueries in the FROM clause. If it was not your
intention to perform a correlated subquery, you may be missing a
table alias from one of your mappers."
if getattr(select, '_correlated', None) is None:
select._correlated = self.select._froms
Index: lib/sqlalchemy/databases/mysql.py
===================================================================
--- lib/sqlalchemy/databases/mysql.py (revision 926)
+++ lib/sqlalchemy/databases/mysql.py (working copy)
@@ -111,6 +111,7 @@
self.module = mysql
self.opts = opts or {}
ansisql.ANSISQLEngine.__init__(self, **params)
+ self.can_correlate_froms = False
def connect_args(self):
return [[], self.opts]
Index: lib/sqlalchemy/engine.py
===================================================================
--- lib/sqlalchemy/engine.py (revision 926)
+++ lib/sqlalchemy/engine.py (working copy)
@@ -183,6 +183,7 @@
self.echo_uow = echo_uow
self.context = util.ThreadLocal(raiseerror=False)
self.tables = {}
+ self.can_correlate_froms = True
self._ischema = None
self._figure_paramstyle()
if logger is None:
--
http://www.alastairs-place.net
-------------------------------------------------------
This SF.net email is sponsored by: Splunk Inc. Do you grep through log files
for problems? Stop! Download the new AJAX search engine that makes
searching your log files as easy as surfing the web. DOWNLOAD SPLUNK!
http://sel.as-us.falkag.net/sel?cmd=lnk&kid=103432&bid=230486&dat=121642
_______________________________________________
Sqlalchemy-users mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/sqlalchemy-users
