Safety of recursive Horn clauses with infinite relations
PODS '87 Proceedings of the sixth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Efficient tests for top-down termination of logical rules
Journal of the ACM (JACM)
A framework for testing safety and effective computability of extended datalog
SIGMOD '88 Proceedings of the 1988 ACM SIGMOD international conference on Management of data
Inference of monotonicity constraints in datalog programs
PODS '89 Proceedings of the eighth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
An axiomatic approach to deciding query safety in deductive databases
Proceedings of the seventh ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
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Datalog (i.e., function‐free logic) programs with monotonicity constraints on extensional predicates are considered. A monotonicity constraint states that one argument of a predicate or a constant is always less than another argument or a constant, according to some strict partial order. Relations of an extensional database are required to satisfy the monotonicity constraints imposed on their predicates. More specifically, a strict partial order is defined on the domain (i.e., set of constants) of the database, and every tuple of each relation satisfies the monotonicity constraints imposed on its predicate. This paper focuses on the problem of entailment of monotonicity constraints in the intensional database from monotonicity constraints in the extensional database. The entailment problem is proven to be decidable, based on a suggested algorithm for computing sound and complete disjunctions of monotonicity and equality constraints that hold in the intentional database. It is also shown that the entailment of monotonicity constraints in programs is a complete problem for exponential time. For linear programs, this problem is complete for polynomial space.