A technique is provided in the present invention for updating a current database without restarting a knowledge-based system (rule-based system, inference system, expert system). The technique allows for the receipt of updates to an earlier database after an inference procedure has started or even after it has ended. The technique calls for the performance of actions necessary to incrementally bring the database to a consistent state by selectively undoing the inferential consequences of not having had the updated fact in the prior inference procedures and redoing the inferential consequences of having the newly received updated fact.