A Sound and Sometimes Complete Query Evaluation Algorithm for Relational Databases with Null Values

ID
TR-83-11
Authors
Raymond Reiter
Publishing date
June 1983
Abstract
This paper presents a sound and, in certain cases, complete method for evaluating queries in relational databases with null values where these nulls represent existing but unknown individuals. The soundness and completeness results are proved relative to a formalization of such databases as suitable theories of first order logic.