
314 Sadri
and
Kowalski
The choice of SLDNF facilitates the comparison of our Consistency Method
for integrity checking with other simplification methods. However, SLDNF
contains a number of inefficiencies. These can be avoided by incorporating the
required features, such as negation as failure, and the ability to reason about
implicit deletions in other, more efficient proof procedures.
Introduction
Informally speaking, integrity constraints are conditions that a database is re-
quired to satisfy as it changes through time. If an update violates these con-
straints, then typically the update is rejected or modified. Alternatively, in
theory,