Integrity constraints in logic databases

We consider logic databases as logic programs and suggest how to deal with the problem of integrity constraint checking. Two methods for integrity constraint handling are presented. The first one is based on a metalevel consistency proof and is particularly suitable for an existing database which has to be checked for some integrity constraints. The second method is based on a transformation of the logic program which represents the database into a logic program which satisfies the given integrity constraints. This method is specially suggested for databases that have to be built specifying, separately, which are the deductive rules and the facts and which are the integrity constraints on a specific relation. Different tools providing for the two mechanisms are proposed for a flexible logic database management system.