Compiling query constraints (extended abstract)

Abstract

We present a general technique to push query constraints (such as length≤1000) into database views and (constraint) logic programs. We introduce the notion of parametrized constraints, which help us push constraints with argument values that are known only at run time, and develop techniques for pushing parametrized constraints into predicate/view definitions. Our technique provides a way of compiling programs with constraint queries into programs with parametrized constraints compiled in, and which can be executed on systems, such as database query evaluation systems, that do not handle full constraint solving. Thereby our technique can push constraint selections that earlier constraint query rewriting techniques could not. Our technique is independent of the actual constraint domain, and we illustrate its use with equality constraints on structures (which are useful in object-oriented query languages) and linear arithmetic constraints.