Fixes:

Fixes:

I have written some patches which add support for NULLs to Postgres95.
In fact support for NULLs was already present in postgres, but it had been
disabled because not completely debugged, I believe. My patches simply add
some checks here and there. To enable the new code you must add -DNULL_PATCH
to CFLAGS in Makefile.global. After recompiling you can do things like:

insert into a (x, y) values (1, NULL);
update a set x = NULL where x = 0;

You can't still use a "where x=NULL" clause, you must use ISNULL instead.
This could probably be an easy fix to do.

Submitted by: Massimo Dal Zotto <dz@cs.unitn.it>