启动服务:
1.在系统服务启动
2.在sql配置管理器服务选项中启动
3.在管理员cmd:net start mssqlserver;net stop mssqlserver
use master go if(not exists(select* from sysdatabases where name='school')) create database school on primary ( name='School_data', filename='E:\School_data.mdf', size=10MB, filegrowth=1MB ) log on ( name='School_log', filename='E:\School_log.ldf', size=2MB, filegrowth=1MB ) go use school create table class(clId int not null identity(1,1) constraint PK_cid primary key,clName varchar(40) not null);//定义自增长主键 create table student(stuId int not null identity(1,1)constraint PK_sid primary key,stuName varchar(20) not null,sex varchar check (sex in('F','M')) not null,clID int constraint FK_StuClass foreign key(clID) references class(clID)) //定义外键约束,检查约束 insert into class(clName) values('软件1班') insert into class(clName) values('软件2班') insert into class(clName) values('软件2班') update class set clName='软件3班' where clId=3 insert into class(clName) values('软件4班') select *from class insert into student(stuName,sex,clID) values('用户1','F',1) insert into student(stuName,sex,clID) values('用户2','M',2) insert into student(stuName,sex,clID) values('用户3','F',3) insert into student(stuName,sex,clID) values('用户4','M',2) insert into student(stuName,sex) values('用户5','M') select *from student //内连接 select student.clID,stuName,clName from student inner join class on student.clId=class.clId order by clId //左连接 select student.clID,stuName,clName from student left join class on student.clId=class.clId where student.clId is null order by clId //右连接 select count(student.clID)as count from student right join class on student.clId=class.clId group by class.clId having count(student.clID)>1 //嵌套查询 select *from student where clId=(select clId from class where clId=2) go use master go if exists(select *from sysdatabases where name='school') drop database school use master go exec sp_detach_db school go exec sp_attach_db school, 'E:\School_data.mdf', 'E:\School_log.ldf' go
use master;
select distinct type from spt_values;
create database hh;
use hh;
drop table ggz;
create table ggz(id int IDENTITY(1,1),num int not null,adds varchar(10))
//添加主键约束
alter table ggz alter column id int not null;
alter table ggz add constraint pk_id primary key(id);
//删除主键约束
alter table ggz drop constraint pk_id;
//添加唯一约束
alter table ggz add constraint UQ_adds unique(adds);
//添加默认约束
alter table ggz add constraint DF_adds default('ca') for adds;
//修改属性
alter table ggz alter column adds varchar(10) null;
//插入
insert into ggz(id,num) values(3,3);
//添加检查约束
alter table ggz add constraint CK_num check(num in(1,0));
//更新
update ggz set num=2 where id=3;
insert into ggz(num) values(0);
//删除
delete from ggz where num=0;