1、创建一个数据库empdb
代码示例:
CREATE DATABASE empdb CHARACTER SET utf8;
2、设计2张表
department部门表:id,dep_name,dep_location
employee员工表:eid,ename,age,dep_id
代码示例:
-- 部门表
-- PRIMARY KEY 主建 AUTO_INCREMENT自增约束
CREATE TABLE department(
id INT PRIMARY KEY AUTO_INCREMENT,
dep_name VARCHAR(30),
dep_location VARCHAR(30));
-- 员工表
-- 外键约束 CONSTRAINT fk_eid FOREIGN KEY (dept_id) REFERENCES department(id))
CREATE TABLE employee(
eid INT PRIMARY KEY AUTO_INCREMENT,
ename VARCHAR(20),
age INT,
dept_id INT,
CONSTRAINT fk_eid FOREIGN KEY (dept_id) REFERENCES department(id));
-- 删除外键约束
ALTER TABLE employee DROP FOREIGN KEY fk_eid;
-- 已存在添加外键约束
ALTER TABLE employee ADD CONSTRAINT fk_eid FOREIGN KEY (dept_id) REFERENCES department(id);
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Mysql数据库常用语句——创建数据库/表
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