Source : Free On-Line Dictionary of Computing

deductive database
     
         A combination of a conventional {database}
        containing {fact}s, a {knowledge base} containing {rule}s, and
        an {inference engine} which allows the derivation of
        {information} implied by the facts and rules.
     
        Commonly, the knowledge base is expressed in a subset of
        {first-order logic} and either a {SLDNF} or {Datalog}
        inference engine is used.
     
        (1995-04-27)