BUG #3296: CASCADING FKs dont DEFER
The following bug has been logged online:
Bug reference: 3296
Logged by: S. Robert James
Email address: srobertjames@vesaria.com
PostgreSQL version: 8.1
Operating system: Linux
Description: CASCADING FKs dont DEFER
Details:
If a FK is set to ON DELETE CASCADE DEFERRABLE INITIALLY DEFERRED, it does
not honor the defer.
That is, if you DELETE a record and then INSERT it back, you still get a FK
deletion of the referencing record. This seems to ignore DEFERRED.
I did not seem to get this on 8.2 / Windows
"S. Robert James" <srobertjames@vesaria.com> writes:
If a FK is set to ON DELETE CASCADE DEFERRABLE INITIALLY DEFERRED, it does
not honor the defer.
That is, if you DELETE a record and then INSERT it back, you still get a FK
deletion of the referencing record. This seems to ignore DEFERRED.
Actually, the cascaded delete happens immediately regardless of "defer"
mode; you can only defer constraint checks, not cascade actions. As far
as I can tell, this is the behavior defined by the SQL spec. Notice in
particular this statement (from SQL92 11.8 <referential constraint
definition>)
9) All rows that are marked for deletion are effectively deleted
at the end of the SQL-statement, prior to the checking of any
integrity constraints.
which makes it clear that the committee thinks that cascade deletes are
separate from constraint checks.
regards, tom lane