I've just put the following code into a before update trigger, for the
purpose of recording updates to a column value:

IF (OLD.mast_Column_Name IS NULL OR
NEW.mast_Column_Name IS NULL) THEN

BEGIN

IF ((OLD.mast_Column_Name IS NULL AND
NEW.mast_Column_Name IS NOT NULL) OR
(OLD.mast_Column_Name IS NOT NULL AND
NEW.mast_Column_Name IS NULL)) THEN

EXECUTE PROCEDURE Audit_The_Change(parameters, ...);

END

ELSE IF (OLD.mast_Column_Name <> NEW.mast_Column_Name) THEN

EXECUTE PROCEDURE Audit_The_Change(parameters, ...);



This seems a bit long-winded to me, especially if similar code needs
to be repeated for thirty columns. I originally just wanted to write:

IF (OLD.mast_Column_Name <> NEW.mast_Column_Name) THEN
EXECUTE PROCEDURE Audit_The_Change(parameters, ...);


but then I remembered the problem of comparison with NULL.

Does anyone know a better way?


David Trudgett