【SQL数据库】创建公司资料库

橙色为primary key，绿色为foreign key 

employee

emp_id	name	birth_date	sex	salary	branch_id	sup_id
206	小黄	1999/10/8	F	50000	1	NULL
207	小绿	1985/9/16	M	29000	2	206
208	小黑	2000/12/19	M	35000	3	206
209	小白	1997/1/22	F	39000	3	207
210	小兰	1925/11/10	F	84000	1	207

CREATE TABLE `employee`(
	`emp_id` INT PRIMARY KEY,
    `name` VARCHAR(20),
    `birth_date` DATE,
    `sex` VARCHAR(1),
    `salary` INT,
    `branch_id` INT,
    `sup_id` INT
);

为什么没有把branch_id和sup_id设置为foreign key呢？

因为目前还没有创建，现在设定会出错 

branch

branch_id	branch_name	manager_id
1	研发	206
2	行政	207
3	资讯	208

CREATE TABLE `branch`(
	`branch_id` INT PRIMARY KEY,
    `branch_name` VARCHAR(20),
    `manager_id` INT,
    FOREIGN KEY (`manager_id`) REFERENCES `employee`(`emp_id`) ON DELETE SET NULL
);

 foreign key在写的时候，要把对应的表格写上

on delete set null的意思是，如果资料被删掉，那就设置为null

ALTER TABLE `employee`
ADD FOREIGN KEY(`branch_id`)
REFERENCES `branch`(`branch_id`)
ON DELETE SET NULL;

ALTER TABLE `employee`
ADD FOREIGN KEY(`sup_id`)
REFERENCES `employee`(`emp_id`)
ON DELETE SET NULL;

补上`employee`的foreign key 

client

client_id	client_name	phone
400	阿狗	254354335
401	阿猫	25633899
402	旺来	45354345
403	露西	54354365
404	艾瑞克	18783783

CREATE TABLE `client`(
	`client_id` INT PRIMARY KEY,
    `client_name` VARCHAR(20),
    `phone` VARCHAR(20)
);

 创建客户的表格

work_with

emp_id	client_id	total_sales
206	400	70000
207	401	24000
208	400	9800
208	403	24000
210	404	879400

CREATE TABLE `work_with`(
	`emp_id` INT,
    `client_id` INT,
    `total_sales` INT,
    PRIMARY KEY(`emp_id`, `client_id`),
    FOREIGN KEY(`emp_id`) REFERENCES `employee`(`emp_id`) ON DELETE CASCADE,
    FOREIGN KEY(`client_id`) REFERENCES `client`(`client_id`) ON DELETE CASCADE
);

on delete cascade的意思是，如果资料被删掉，那也一起删掉 

1 增加部门的资料

INSERT INTO `branch` VALUES(1, "研发", NULL);
INSERT INTO `branch` VALUES(2, "行政", NULL);
INSERT INTO `branch` VALUES(3, "咨讯", NULL);

为什么不先添加员工的资料？

因为`employee`的foreign key没有对应

当然，`branch`的foreign key也会出错，因此，先把manager_id设置为null

2 增加员工的资料

INSERT INTO `employee` VALUES(206, "小黄", "1998-10-08", "F", 50000, 1, NULL);
INSERT INTO `employee` VALUES(207, "小绿", "1985-09-16", "M", 29000, 2, 206);
INSERT INTO `employee` VALUES(208, "小黑", "2000-12-19", "M", 35000, 3, 206);
INSERT INTO `employee` VALUES(209, "小白", "1997-01-22", "F", 39000, 3, 207);
INSERT INTO `employee` VALUES(210, "小兰", "1925-11-19", "F", 84000, 1, 207);

此时，不会再出错了

3 修改manager_id

UPDATE `branch`
SET `manager_id` = 206
WHERE `branch_id` = 1;

UPDATE `branch`
SET `manager_id` = 207
WHERE `branch_id` = 2;

UPDATE `branch`
SET `manager_id` = 208
WHERE `branch_id` = 3;

4 增加客户的资料

INSERT INTO `client` VALUES(400, "阿狗", "254354335");
INSERT INTO `client` VALUES(401, "阿猫", "25633899");
INSERT INTO `client` VALUES(402, "旺来", "45354345");
INSERT INTO `client` VALUES(403, "露西", "54354365");
INSERT INTO `client` VALUES(404, "艾瑞克", "18783783");

5 增加销售业绩资料

insert into `work_with` values(206, 400, '70000');
insert into `work_with` values(207, 401, '24000');
insert into `work_with` values(208, 402, '9800');
insert into `work_with` values(208, 403, '24000');
insert into `work_with` values(210, 404, '87940');