On Negative Information in Deductive Databases

Marek A. Suchenek, Rajshekhar Sunderraman
1990 Journal of Database Management  
This paper provides an overview of deductive data bases, with an emphasis on problems related to negative information. It embeds this subject into a wider context of logic programming, exposing certain peculiarities pertinent to treatment of negation in these fields. Program clause: sub − component(X 1 , Y 1 ) ← component(X 1 , Y 1 ) Unification substitution: P 4 for X 1 and X for Y 1 Modified query clause: ← component(P 4 , X) Program clause: component(P 4 , P 7 ) ← Unification substitution: P
more » ... 7 for X Modified query clause: 2 Answer to query: X = P 7 2. Query clause: Unification substitution: P 4 for X 1 and X for Y 1 Modified query clause: ← component(P 4 , X) Program clause: component(P 4 , P 8 ) ← Unification substitution: P 8 for X Modified query clause: 2 Answer to query: X = P 8 Query clause: Unification substitution: P 4 for X 1 and X for Y 1 Modified query clause: ← component(P 4 , Z 1 ), sub − component(Z 1 , X) Program clause: component(P 4 , P 7 ) ← Unification substitution: P 7 for Z 1 Modified query clause: ← sub − component(P 7 , X) Program clause: sub − component(X 1 , Y 1 ) ← component(X 1 , Y 1 ) Unification substitution: P 7 for X 1 and X for Y 1 Modified query clause: ← component(P 7 , X) Program clause: component(P 7 , P 9 ) ← Unification substitution: P 9 for X Modified query clause: 2 Answer to query: X = P 9 4. Query clause: ← sub − component(P 4 , X) Program clause: sub−component(X 1 , Y 1 ) ← component(X 1 , Z 1 ), sub− component(Z 1 , Y 1 ) Unification substitution: P 4 for X 1 and X for Y 1
doi:10.4018/jdm.1990070103 fatcat:zlobe4zujzbj3iihylks2hkfxq