(i9) United States
(12) Patent Application Publication
Bestgen et al.
(54) METHOD AND APPARATUS FOR
ELIMINATING PARTITIONS OF A
DATABASE TABLE FROM A JOIN QUERY
USING IMPLICIT LIMITATIONS ON A
PARTITION KEY VALUE
(75) Inventors: Robert Joseph Bestgen, Dodge Center,
MN (US); Shantan Kethireddy,
Rochester, MN (US); Jeffrey Wayne
Tenner, Rochester, MN (US)
Correspondence Address:
IBM CORPORATION
ROCHESTER IP LAW DEPT. 917
3605 HIGHWAY 52 NORTH
ROCHESTER, MN 55901-7829 (US)
(73) Assignee: International Business Machines Corporation, Armonk, NY
(21) Appl. No.: 11/191,470
(22) Filed: Jul. 28, 2005
Publication Classification
(51) Int. CI.
G06F 17/30 (2006.01)
(52) U.S. CI 707/5
(57) ABSTRACT
A database facility supports database join queries in a database environment having at least one database table divided into multiple partitions based on a partition key value. The facility determines whether the values in a table joined to the partitioned table place an implicit limitation on the partition key, and eliminates from query evaluation any partitions which do not satisfy the implicit limitation. Preferably, the database uses a star schema organization, in which implicit limitations in a relatively small dimension table are used to eliminate partitions in a relatively large fact table.
