On the Soundness Property for SQL Queries of Fine-grained Access Control in DBMSs

The fine-grained access control approaches in DBMSs should satisfy soundness property which requires the answer of a query returned by the approach under the control of fine-grained access control is consistent with the answer when there is no fine-grained access control. However, existing techniques cannot guarantee soundness property for all SQL queries. Therefore, for an approach, there is a practical need to state that, for which kinds of SQL queries, soundness property can be guaranteed by this approach. In this paper, we present our initial effort for this objective. We firstly proposed a new algorithm with query modification. Then, we refine, extend and enhance the theory about soundness property, and state that, for which kinds of SQL queries, the soundness property is guaranteed by the proposed algorithm. Finally, we implement the algorithm using query modification and performance evaluation has also been conducted, which indicates this approach is feasible.