  We consider the problems of finding and determining certain query answers and
of determining containment between queries; each problem is formulated in
presence of materialized views and dependencies under the closed-world
assumption. We show a tight relationship between the problems in this setting.
Further, we introduce algorithms for solving each problem for those inputs
where all the queries and views are conjunctive, and the dependencies are
embedded weakly acyclic. We also determine the complexity of each problem under
the security-relevant complexity measure introduced by Zhang and Mendelzon in
2005. The problems studied in this paper are fundamental in ensuring correct
specification of database access-control policies, in particular in case of
fine-grained access control. Our approaches can also be applied in the areas of
inference control, secure data publishing, and database auditing.
