SQL Server学习笔记3：数据库中表的插入、删除、修改、合并

建立数据库

create database zhangjiaxing

自动定位到建立的数据库

use zhangjiaxing

建立数据表

students表

create table students
(
    sno char(5) primary key,
    sname char(20) not null unique,
    ssex char(2) constraint de_ssex default '男',
    sage int check (sage between 16 and 24),
    sdept char(15) check (sdept in ('电子商务','计算机','数学'))
)

courses表

create table courses
(
    cno char(5) primary key,
    cname char(20) not null,
    pre_cno char(5) references courses(cno),
    credits int,
);

reports表

create table reports
(
    sno char(5) references students(sno),
    cno char(5) references courses(cno),
    grade int check (grade>=0 and grade<=100),
    constraint sno_cno primary key(sno,cno)
);

插入数据

表的关系

向students表中插入数据

/*insert into students values('s01','王建平','男',21,'电子商务')
insert into students values('s02','刘华','女',19,'电子商务')
insert into students values('s03','范林军','女',18,'计算机')
insert into students values('s04','李伟','男',19,'计算机')
insert into students values('s05','黄河','男',18,'数学')
insert into students values('s06','长江','男',20,'数学')
insert into students values('s38','张家兴','男',22,'计算机')*/
select * from students

向courses表插入数据

/*insert into courses values('c01','英语',null,4)
insert into courses values('c05','C++',null,3)
insert into courses values('c02','数据结构','c05',2)
insert into courses values('c03','数据库','c02',2)
insert into courses values('c04','DB_设计','c03',3)
insert into courses values('c07','操作系统','c05',3)
insert into courses values('c06','网络原理','c07',3)*/
select * from courses

注意要根据表的关系来定插入表的顺序

向reports表添加数据（使用企业管理器管理表格数据）

修改表的数据
将students表中sno=s01的同学的sage改为22

update students set sage=22 where sno='s01'

将students表中sno=s03的同学的ssex改为男，sage改为17

update students set ssex='男',sage=17 where sno='s03'

将students表中所有人的sage+1

update students set sage=1+sage

数据库表的合并（条件合并）

select * 
from students,courses,reports
where students.sno=reports.sno
and courses.cno=reports.cno