Access control in a relational data base management system by query modification

This work describes the access control system being implemented in INGRES (INteractive Graphics and REtrieval System). The scheme can be applied to any relational data base management system and has several advantages over other suggested schemes. These include: a) implementation ease b) small execution time overhead c) powerful and flexible controls d) conceptual simplicity The basic idea utilized is that a user interaction with the data base is modified to an alternate form which is guaranteed to have no access violations. This modification takes place in a high level interaction language. Hence, the processing of a resulting interaction can be accomplished with no further regard for protection. In particular, any procedure calls in the access paths for control purposes, such as in [1,2], are avoided.