前段时间学习了MySQL数据库,今天考了一次数据库的测验,结果没考好,我发现数据库真的是 逻辑 比 代码 重要多了!将例题与代码总结于此,以便今后查漏补缺,数据库的知识点实在太密集了,之后再总结到这个MySQL专栏里
-- 创建部门表
DROP TABLE IF EXISTS dept;
CREATE TABLE dept(
-- 部门编号
deptno int PRIMARY KEY,
-- 部门名称
dname VARCHAR(14),
-- 部门所在地
loc VARCHAR(13)
);
-- 向部门表插入数据
INSERT INTO dept VALUES (10,'ACCOUNTING','NEW YORK');
INSERT INTO dept VALUES (20,'RESEARCH','DALLAS');
INSERT INTO dept VALUES (30,'SALES','CHICAGO');
INSERT INTO dept VALUES (40,'OPERATIONS','BOSTON');
-- 创建员工表
DROP TABLE IF EXISTS emp;
CREATE TABLE emp(
-- 员工编号
empno int PRIMARY KEY,
-- 员工姓名
ename VARCHAR(10),
-- 工作岗位
job VARCHAR(9),
-- 直属领导
mgr int,
-- 入职时间
hiredate DATE,
-- 工资
sal double,
-- 奖金
comm double,
-- 所属部门
deptno int
);
-- 为员工表表添加外键约束
ALTER TABLE emp ADD CONSTRAINT FOREIGN KEY EMP(deptno) REFERENCES dept (deptno);
-- 向员工表插入数据
INSERT INTO emp VALUES(7369,'SMITH','CLERK',7902,"1980-12-17",800,NULL,20);
INSERT INTO emp VALUES(7499,'ALLEN','SALESMAN',7698,'1981-02-20',1600,300,30);
INSERT INTO emp VALUES(7521,'WARD','SALESMAN',7698,'1981-02-22',1250,500,30);
INSERT INTO emp VALUES(7566,'JONES','MANAGER',7839,'1981-04-02',2975,NULL,20);
INSERT INTO emp VALUES(7654,'MARTIN','SALESMAN',7698,'1981-09-28',1250,1400,30);
INSERT INTO emp VALUES(7698,'BLAKE','MANAGER',7839,'1981-05-01',2850,NULL,30);
INSERT INTO emp VALUES(7782,'CLARK','MANAGER',7839,'1981-06-09',2450,NULL,10);
INSERT INTO emp VALUES(7788,'SCOTT','ANALYST',7566,'1987-07-03',3000,NULL,20);
INSERT INTO emp VALUES(7839,'KING','PRESIDENT',NULL,'1981-11-17',5000,NULL,10);
INSERT INTO emp VALUES(7844,'TURNER','SALESMAN',7698,'1981-09-08',1500,0,30);
INSERT INTO emp VALUES(7876,'ADAMS','CLERK',7788,'1987-07-13',1100,NULL,20);
INSERT INTO emp VALUES(7900,'JAMES','CLERK',7698,'1981-12-03',950,NULL,30);
INSERT INTO emp VALUES(7902,'FORD','ANALYST',7566,'1981-12-03',3000,NULL,20);
INSERT INTO emp VALUES(7934,'MILLER','CLERK',7782,'1981-01-23',1300,NULL,10);
-- 创建工资等级表
DROP TABLE IF EXISTS salgrade;
CREATE TABLE salgrade(
-- 等级
grade int,
-- 最低工资
losal double,
-- 最高工资
hisal double
);
-- 向工资等级表插入数据
INSERT INTO salgrade VALUES (1,700,1200);
INSERT INTO salgrade VALUES (2,1201,1400);
INSERT INTO salgrade VALUES (3,1401,2000);
INSERT INTO salgrade VALUES (4,2001,3000);
INSERT INTO salgrade VALUES (5,3001,9999);