
Chapter
7:
Foundations
of
Semantic
Query
Optimization
265
H— Pl*,...,Pm* {Rl;...;Rn} (terms omitted).
Here,
H — Pl*,...,Pm*
is a (compiled) axiom A, and Rl,...,Rn are the residues of A with the in-
tegrity constraints that are merge compatible with A. •
The process of residue generation can be applied to extensional predicates
also by applying the "axiom" P*-«- P* for the predicate P*. This way we ob-
tain semantically constrained extensional predicates which may be useful for
processing queries for a non-deductive (or the extensional portion of a
deductive) database.
Procedurally, a semantically constrained axiom, as given in the definition ...