foreign key problem

I have two tables:

create table table1
( vers integer,
table1_id text NOT NULL,
desc text,
PRIMARY KEY (rev, table1)id)
);

create table table2
( vers integer,
othertble_id text NOT NULL,
table1_id text,
FOREIGN KEY (rev, othertable_id) REFERENCES othertable
ON UPDATE CASCADE ON DELETE CASCADE,
FOREIGN KEY (rev, table1_id) REFERENCES table1
ON UPDATE CASCADE ON DELETE CASCADE,
PRIMARY KEY (rev, othertable_id, table1_id)
);

As you can see, table2 has a foreign key reference to table1 and also
includes on delete cascade (and on update cascade).

There has been a lot of activity in this database on these tables in
particular in the last several days and somehow we've ended up with rows in
table2 that have table1_ids that do not exist in table1.

How is this possible? I've tried to reproduce this, but haven't been able
to yet. This has happened to use several times.

Thanks for any help,

--
Laurette Cisneros
The Database Group
(510) 420-3137
NextBus Information Systems, Inc.
www.nextbus.com
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