sql server 建表，增删改练习

use master
--drop database Class

create database Class
on primary(
    name='Class',
    filename='D:\SQLTest\Class.mdf',
    size=10mb,
    filegrowth=10mb
)
log on(
    name='Class_log',
    filename='D:\SQLTest\Class_log.ldf',
    size=5mb,
    filegrowth=10%
)

use Class--使用数据库
truncate table ClassInfo

--创建班级信息表格
create table Classinfo(
    classId int identity(1,1) primary key not null,--后面三个参数分别是 自增(start=1,step=1),主键，非空
    className nvarchar(10) not null --nvarchar 使用Unicode编码，长度可变字符串
)

--插入数据
insert into Classinfo(className)
values('计科1'),('计科2'),('计科3'),('计科4')
select * from Classinfo

--创建学生信息表格
create table StuInfo(
    stuId int identity(1,1) primary key not null,
    stuName nvarchar(10) not null,
    stuSexy bit default(0) not null,--默认值为0
    stuBirthday date not null,
    stuPhone char(11),
    stuEmail varchar(20),
    classId int not null,
    foreign key (classId) references ClassInfo(ClassId) --classId作为外键，是从ClassInfo的ClassId引用过来的
)

--添加学生信息
insert into StuInfo
values('zsben',1,'1999-1-26','','1249461124@qq.com',1),
('zsben2',1,'1999-1-26','','1249461124@qq.com',2)
select * from StuInfo

--创建科目表
create table CourseInfo(
    cId int identity(1,1) primary key not null,
    cName nvarchar(20) not null
)

--插入科目信息
insert into CourseInfo
values('数据库'),('算法设计'),('计算机网络')
select * from CourseInfo

--drop table ScoreInfo

--创建成绩信息表
create table ScoreInfo(
    scoreId int identity(1,1) primary key not null,
    score int not null,
    classId int not null,
    foreign key (classId) references Classinfo(ClassId),
    StuId int not null,
    foreign key (StuId) references StuInfo(StuId)
)

select * from Classinfo
select * from StuInfo
select * from CourseInfo
select * from ScoreInfo

update Classinfo set className='数媒1'
where className='计科3'

delete Classinfo where className='计科4'

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