Index is a schema object which contains an entry for each value that appears in the indexed column(s) of the table or cluster. Index provides direct, fast access to rows.
CREATE TABLE MYEmp AS SELECT * FROM Emp; Table created. DESC MYEmp Name Null? Type ------------------------ -------- ----------------- EMPNO NUMBER(4) ENAME VARCHAR2(10) JOB VARCHAR2(9) MGR NUMBER(4) HIREDATE DATE SAL NUMBER(7,2) COMM NUMBER(7,2) DEPTNO NUMBER(2) CREATE INDEX Idx_MYEmp_Empno ON MYEmp(Empno); Index created.