Example of Cluster Index:

The following instance creates the cluster along with tables.

CREATE CLUSTER CLEMP(deptno NUMBER(3));

Create index clind on cluster clemp;

Create table dept (deptno number(3),dname varchar2(20),loc varchar2(20)) cluster clemp(deptno);# for creating index on cluster#

Create table emp(empno number,ename varchar2(20),deptno number(3)) cluster clemp(deptno); # for creating index on cluster#

A rowid of the first deptno will be the same when records are selected,.

Output:

SELECT ROWID FROM CLUSTER clemp;

ROWID

------------------

AAAAzmAAFAAAAJ+AAA

AAAAzmAAFAAAAJ/AAA

AAAAzmAAFAAAAKAAAA

AAAAzmAAFAAAAKBAAA

AAAAzmAAGAAAAIAAAA

Dropping Clusters

A Cluster are dropped by using DROP CLUSTER command.

Example:

DROP CLUSTER CLEMP INCLUDING TABLES;