Towards a Flexible User Interface to Relational Database Systems: Processing Simple Second Order Queries

In this paper, we present a mechanism for answering simple second order queries of the form. "Retrieve connection between attributes A arid S." By connection between A and B" we mean any and all meaningful relationships that can be established between A and B in a given database. What gives our queries their second order nature is the fact that semantics of connections is independent of a particular set of predicates comprising the database scheme. The answers to them. However, depend on which relationships are considered meaningful; this, in turn, depends on the Particular structure of the database scheme and, also, on additional semantic information carried by roles. While we can treat our queries as intentionally second order queries directed at the database instance, we could also treat them as incompletely specified queries posed by a user whose knowledge of the database structure is partial. In this paper, we present a formal characterization of meaningful relationships in present algorithms for computing connections, and describe how our method can be extended to sets containing any number of attributes.Technical report DCS-TR-14