Key points are not available for this paper at this time.
This paper proposes two major extensions to the authorization model for System R relational database management system. The first extension concerns the revoke operation. The revised model provides for a new type of revoke operation, called noncascading revoke, in addition to the System R cascading revoke operation. Unlike cascading revoke, noncascading revoke operation does not recursively remove privileges from users. The second extension concerns negative authorization. The details related to its application are specified in the paper.
Bertino et al. (Fri,) studied this question.