In this work we consider exactly this scenario, where a set of semanticallyrelated relations are hidden while for another set the complete contents are visible. We will consider semantic relationships specified in a variety of languages that are rich enough to capture complex relationships between sources, including relationships that arise in **data** integration, as well as common integrity constraints within a single source, such as referential constraints. The basic analysis problem we will consider will be the following: given a schema and a (for simplicity, Boolean) query Q, can we infer using **data** and schema information that the result of Q is true or that the result is false.