Languages for Relational Databases over Interpreted Structures

We rework parts of the classical relational theory when the underlying domain is a structure with some interpreted operations that can be used in queries. We identify parts of the classical theory that go through `as before' when interpreted structure is present, parts that go through only for classes of nicely-behaved structures, and parts that only arise in the interpreted case. The rst category includes a number of results on equivalence of query languages, as well as expressive power characterizations for the active-domain semantics for a variety of logics. The second category includes most of our results on the natural semantics, including results on cases where the natural semantics collapses to the active semantics. While these collapse results have been proved by nonconstructive means for rst-order logic in previous work, we here give a set of algorithms for eliminating unbounded quanti cations in favor of bounded ones. Furthermore, we show these results for a new class o...

• Type: Conference
• Year: 1997
• Where: PODS
• Authors: Michael Benedikt, Leonid Libkin
• Keywords: Classical Relational Theory, Database, Interpreted Structures, Natural Semantics, PODS 1997