386 ◾ Appendix B
If we are to grant John read access to the employees who earn less than 30K,
then this assertion is specified as follows:
GRANT JOHN READ
EMP
Where EMP.SALARY < 30K
Note that the assertions we have specified are not standard assertions. ese are
some of our ideas. We need to explore ways of incorporating these assertions into
the standards. SQL extensions have also been proposed for RBAC. In fact, products
such as Oracle’s Trusted database enforce RBAC. e access control rules are speci-
fied in an SQL-like language.
B.3.5 Query Modification
Query modification was first proposed in the INGRES project at the University of
California at Berkeley (see Stonebraker and Wong 1974). e idea is to modify the
query based on the constraints. W ...