Reasoning About Conjunctive Query Containment Under Constraints

Reasoning About Conjunctive Query Containment Under Constraints was an EPSRC funded research project.

Brief Description

Description Logics (DLs) have long been recognised as appropriate reasoning tools for a variety of information systems applications, and it has recently been shown that an expressive DL can be used to capture and reason about many popular conceptual modelling formalisms. This approach has been successfully applied in the I-com tool, which supports conceptual modelling and schema integration by using the FACT DL system to verify the model, inferring implicit constraints and checks for inconsistencies.

In the proposed research, we will build on this success by developing a tool that uses DL reasoning to decide query containment problems with respect to a set of constraints (typically a conceptual schema). This is an important problem in general, and is fundamental to information integration where the constraints can include several integrated schemas as well as azioms specifying inter-schema constraints. In this context the various source elements can be treated as views over the global schema, and query containment then becomes the basic reasoning task underlying query rewriting and optimisation.