21. The method of claim 20, wherein the selecting step comprises: forming a hybrid automaton based on a state of the pruned automaton and a schema of the database; simulating the hybrid automaton against the pruned automaton; and selecting the state based on a result of the simulating step.
21. The method of claim 20, wherein the selecting step comprises: forming a hybrid automaton based on a state of the pruned automaton and a schema of the database; simulating the hybrid automaton against the pruned automaton; and selecting the state based on a result of the simulating step. 25. The method of claim 21, wherein the selecting step selects the state only if a simulation exists.