Constraint query languages (preliminary report)

Abstract

We discuss the relationship between constraint programming and database query languages. We show that bottom-up, efficient, declarative database programming can be combined with efficient constraint solving. The key intuition is that the generalization of a ground fact, or tuple, is a conjunction of constraints. We describe the basic Constraint Query Language design principles, and illustrate them with four different classes of constraints: Polynomial, rational order, equality, and Boolean constraints.