Oracle 索引

employee表创建索引

/*
===========================================================
|          为employee表创建索引
============================================================
*/
-- 主键列创建反向键索引
CREATE UNIQUE INDEX idx_empno ON employee(empno) REVERSE;

ALTER TABLE employee 
ADD CONSTRAINT PK_empno 
               PRIMARY KEY(empno) USING INDEX ix_empno;

--创建B树索引
CREATE INDEX idx_emp_department
       ON employee(deptno);

--创建位图索引
CREATE BITMAP INDEX idx_emp_job
       ON employee(job);
       
--创建组合索引
CREATE INDEX idx_emp_name
       ON employee(last_name,first_name);
       

 

主键列创建反向键索引

/*
===========================================================
|          主键列创建反向键索引
============================================================
*/
CREATE UNIQUE INDEX idx_empno ON employee(empno) REVERSE;

ALTER TABLE employee ADD CONSTRAINT PK_empno PRIMARY KEY(empno) USING INDEX idx_empno;

select * FROM employee WHERE empno=7900;