This figure compares the structure clustered tables to the structure of nonclustered tables. One illustration shows two tables as nonclustered tables. There are two distinct tables, EMP and DEPT.

The EMP table contains (among other columns) the following columns:
EMPNO
ENAME
DEPTNO

The DEPT table contains the columns:
DEPTNO
DNAME
LOC

There is another illustration that shows the EMP table and DEPT table created as clustered tables. The cluster key is shown as DEPTNO. The information relating to DEPTNO is shown stored together in the cluster. Specifically EMPNO, ENAME, and the other columns in the EMP table are all stored with the department data. Effectively, all data has been stored together in the same table (cluster).