On domain independent disjunctive databases

We extend the concept of domain independence from queries and databases to disjunctive databases. Informally, a domain independent disjunctive database is one for which the set of correct answers to any domain independent query is independent of the domains of variables in the database statements. We prove that every allowed stratified disjunctive database is domain independent and that every domain independent disjunctive database has an equivalent allowed disjunctive database. We also discuss a generalization and properties of two alternative definitions.