[ORACLE]
allow_null_key= 0
An attempt to
create a record with null primary keys on Oracle will generate a
constraint violation. Normally this would cause system error 311 to
be generated. You can set allow_null_key=1 for this error to be ignored.
Note that this does not actually enable you to create records with null keys - it just stops programs that do create them from terminating with a system error.