Obtaining Information about Queries behind Views and Dependencies


We consider the problems of finding and determining<lb>certain query answers and of determining containment<lb>between queries; each problem is formulated in pres-<lb>ence of materialized views and dependencies under the<lb>closed-world assumption. We show a tight relation-<lb>ship between the problems in this setting. Further,<lb>we introduce algorithms for solving each problem for<lb>those inputs where all the queries and views are con-<lb>junctive, and the dependencies are embedded weakly<lb>acyclic [13]. We also determine the complexity of each<lb>problem under the security-relevant complexity mea-<lb>sure introduced in [31]. The problems studied in this<lb>paper are fundamental in ensuring correct specification<lb>of database access-control policies, in particular in case<lb>of fine-grained access control. Our approaches can also<lb>be applied in the areas of inference control, secure data<lb>publishing, and database auditing.


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