Mysql 数据库:如何创建更新级联表和查询数据?
我想创建一个有两个表的数据库。我想在两个表之间创建一个更新级联关系。如果在EMPLOYEE中更改了SNAME,那么WORKREPORT也将更改他的SNAMEMysql 数据库:如何创建更新级联表和查询数据?,mysql,database,cascade,Mysql,Database,Cascade,我想创建一个有两个表的数据库。我想在两个表之间创建一个更新级联关系。如果在EMPLOYEE中更改了SNAME,那么WORKREPORT也将更改他的SNAME EMPLOYEE: SNO SNAME SPASSWORD SEX BDATE HEIGHT BTITLE 2014 boss 12345 male 1987-06-02 180 Mana
EMPLOYEE:
SNO SNAME SPASSWORD SEX BDATE HEIGHT BTITLE
2014 boss 12345 male 1987-06-02 180 Manager
2015 Tom 1234567 male 1987-06-05 180 Employee
WORKREPORT
SNO SNAME SDATA SCHECKLIST SIMAGE
2014 boss 1987-06-02 abc afafafaf
2015 Tom 1987-06-05 affafa afafafaf
我的代码运行得很好。我的问题是:我不知道如何从“工作报告”中只查询员工的信息(而不是经理),假设有很多员工。我该怎么办?我设计“工作报告”的想法对吗?
这是我的代码:
CREATE database if not exists cm360_cm360_1;
use cm360_cm360_1;
CREATE TABLE IF NOT EXISTS EMPLOYEE(SNO VARCHAR(7) NOT NULL, SNAME VARCHAR(8) NOT NULL, SPASSWORD VARCHAR(11) NOT NULL,SEX VARCHAR(8) NOT NULL, BDATE DATETIME NOT NULL, HEIGHT DEC(5,2) DEFAULT 000.00,BTitle VARCHAR(15) NOT NULL, PRIMARY KEY(SNO), UNIQUE KEY (SNAME))ENGINE=InnoDB ;
SET SQL_SAFE_UPDATES=0;
INSERT INTO EMPLOYEE VALUES (2014,'boss','12345','male','2014-6-10 11:00:00',160.00,'Manager');
INSERT INTO EMPLOYEE VALUES (2015,'Tom','1234567','male','2014-6-10 12:00:00',160.00,'Employee');
SELECT * FROM EMPLOYEE;
CREATE TABLE IF NOT EXISTS WORKREPORT(SNO VARCHAR(7) NOT NULL, SNAME VARCHAR(8) NOT NULL,SDATA DATETIME , SCHECKLIST VARCHAR(150),SIMAGE VARCHAR(20),FOREIGN KEY (SNO) REFERENCES EMPLOYEE (SNO) ON UPDATE CASCADE,FOREIGN KEY(SNAME) REFERENCES EMPLOYEE (SNAME) ON UPDATE CASCADE ) ENGINE=InnoDB;
INSERT INTO WORKREPORT VALUES (2014,'boss',' 2014-6-10 14:38:59','abc','afdsfdfds');
INSERT INTO WORKREPORT VALUES (2015,'Tom',' 2014-6-10 15:38:59','abc','afdsfdfds');
SELECT * FROM WORKREPORT order by SDATA ASC;
UPDATE WORKREPORT SET SCHECKLIST='elevator;floor' WHERE SNAME='hanlu2';
delete from workreport WHERE SIMAGE='N/A' AND SNAME='enlan';
如果您想获取员工工作报告信息,下面的查询应该可以
SELECT WORKREPORT.*
FROM WORKREPORT, EMPLOYEE
WHERE EMPLOYEE.SNO = WORKREPORT.SNO
AND EMPLOYEE.BTITLE = "Employee"
如果您只想获取所有员工信息,您可以
连接SNO
和/或SNAME
上的两个表,因为这些列上有FK关系,并根据BTITLE
不应为MANAGER
的条件进行筛选
select e.*
from employee e
join workreport w on e.SNO = w.SNO
and e.SNAME = w.SNAME
and e.BTITLE <> 'Manager'
选择e*
来自雇员e
在e.SNO=w.SNO上连接工作报告w
e.SNAME=w.SNAME
和e.B标题“经理”
您正在使用更新级联上的
。它不管用吗?它很管用。我的问题是:我不知道如何从“工作报告”中查询员工的信息,假设有很多员工,只需使用Fk列在表之间进行连接即可。