Stefan He could have had multiple windows (sqlplus sessions) going. Not likely, but just taking it off the table. On Wed, Nov 10, 2010 at 9:14 AM, Stefan Knecht <knecht.stefan@xxxxxxxxx>wrote: > Michael > > If you issue DDL commands (add constraint, drop constraint etc) against a > table, any uncommitted transactions of your session are automatically > committed. If the commit fails (due to constraints, or triggers, for > example), the DDL fails. > > If another user has open transactions, your DDL will abort (or wait / hang) > > Stefan > > > ========================= > > Stefan P Knecht > CEO & Founder > s@xxxxxxxx > > 10046 Consulting GmbH > Schwarzackerstrasse 29 > CH-8304 Wallisellen > Switzerland > > Phone +41-(0)8400-10046 > Cell +41 (0) 79 571 36 27 > info@xxxxxxxx > http://www.10046.ch > > ========================= > > > On Wed, Nov 10, 2010 at 6:03 PM, Michael Moore <michaeljmoore@xxxxxxxxx>wrote: > >> >> Do you have any un commited transactions against this table? > > >