DB2 V10-New Access Method~Hashing (1 of 2)

Posted by

Up to Db2 V10, data in the db2 can be accessed by either Indexing or Scanning. The new method is called Hashing. Hashing-it is not New. It is old technology. IMS databases founded upon hashing.

Hashing in DB2
Hashing in DB2

Hash function is an algorithm. It converts data elements into a single integer. This number serves an index to database.

How to create table with Hash function?

CREATE TABLE DSN81010.DEPT
 (DEPTNO    CHAR(3) NOT NULL,
   DEPTNAME  VARCHAR(36) NOT NULL,
   MGRNO     CHAR(6),
   ADMRDEPT  CHAR(3) NOT NULL,
   LOCATION  CHAR(16),
   PRIMARY KEY (DEPTNO)
 )
   IN DSN8D10A.DSN8S10D
   ORGANIZE BY HASH UNIQUE (DEPTNO)
   HASH SPACE 64 M;

Hash space: It is defined area used for Hash access.

Related articles