
Chapter 9: Database Integrity 339
lead to finitely failed search spaces, and our method is complete for the given
case,
then the transaction satisfies the constraints.
We believe that our method is as complete as SLDNF. We will discuss this
point later in "Correctness and Completeness of the Consistency Method."
SLDNF has been proved complete for several restricted classes of databases
(Clark [1978], Jaffar, Lassez, and Lloyd [1983]), which include hierarchical
databases such as those before and after the update in the following example.
(A database is hierarchical if it contains no recursion. See Clark [1978] for a
more precise definition. ...