The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 09, 2000
Filed:
May. 23, 1997
Divesh Srivastava, New Providence, NJ (US);
Peter J Stuckey, Elwood, AU;
Sundararajarao Sudarshan, Powai, IN;
Lucent Technologies Inc., Murray Hill, NJ (US);
Abstract
An equivalence rule having the multiset version of the relational algebraic theta-semijoin operator is used in effectuating Constraint Magic rewriting on a computer programming language query having non-equality, as well as equality, predicates. In particular, the rule effectuates Constraint Magic rewriting for a single join. When applied repeatedly on a sequence of joins, Constraint Magic rewriting is effectuated for a single block query. The rule may be used to generate relational algebraic expressions to optimize or determine the equivalency of queries. Cost estimates for alternative ways of evaluating a complex query can be efficiently computed. Based on these computed cost estimates, the least costly implementation of a complex query is determined.