sqlserver

----sqlserver基礎知識點集合----
--1.表相關
--建庫
create database mytest
--使用庫
use mytest
--建表
create table td_user (
[Id] [int] IDENTITY(1,1) NOT NULL PRIMARY KEY,--主鍵約束,自增
[UserName] nvarchar NOT NULL unique, --唯一性約束
[UserPwd] nvarchar NOT NULL,
[UserMail] nvarchar NOT NULL,
[age] [int] check (age>=0 and age<=100) NOT NULL,--條件約束
[CreateTime] [datetime] NOT NULL default getdate() --默認值
)
/
数据完整性=数据的有效性和正确性(完整性=有效,正确)
完整性约束
1.唯一约束(允许一行数据为空)
2.主键约束(唯一约束+ 非空约束)
3.默认值约束
4.check约束
5.主外键约束
6.非空约束
一个表在不同的关系中既可以是主表又可以是子表
主外键是一对多关系
/
create table student(
--字段名数据类型约束(一般在此只加非空约束)
stuId int not null,
stuName varchar(20) not null,
stuAge int not null,
stuSex bit not null,
stuTel varchar(13) not null,
stuAddress varchar(30)
)
go
--添加主键约束
alter table student
add constraint PK_stuId primary key (stuId)
--添加唯一约束
alter table student
add constraint UQ_stuName unique (stuName)
--添加check约束
alter table student
add constraint CK_stuAge check (stuAge >=18 and stuAge <= 35)
--添加默认约束
alter table student
add constraint DF_stuAddress default ('地址不详') for stuAddress
go
--添加外键约束
alter table exam --修改外键表
add constraint FK_stuId
foreign key(stuId) references student(stuId)
--外键表字段 主键表字段
--删除约束(alter table 表名drop constraint 约束名)
alter table exam
drop constraint FK_stuId
Go
/哪个是外键表，就给它添加外键约束
给表添加主外键约束的时候遵循个一致
1.外键表外键与主键表主键数据类型一致(语法规范)
2.长度一致(语法规范)
3.名称一致(一般是项目规范，名称最好是一致)
/
/索引/

-------------------------------存储过程Study------------------------------

--删除表
drop table student
go

---

---

--创建用户信息数据表
create table student
(
id int identity(1,1),--递增,
stuNo varchar(50) primary key, --唯一键
stuName varchar(50),
stuAge datetime,
stuSex varchar(5)
)

--创建用户分数数据表
create table course
(
id int identity(1,1),--递增,
stuNo varchar(50),
courseName varchar(50),
courseScore decimal
)

---

---

--插入数据
--插入单条数据
insert into student(stuNo,stuName,stuAge,stuSex) values('01','王男','1996-08-27 09:00:00.000','男')

--多数量插入数据
--SQL Server2008特有的插入
insert into student values('02','杨幂','1995-4-20 6:0:0','女'),
('03','程峰','1988-9-17 15:30:0','男')

insert into course values('02','思想政治','85.5'),
('02','数学','70'),
('02','语文','80'),
('02','物理','90'),
('02','化学','65'),
('02','英语','96')

insert into course values('03','思想政治','60'),
('03','数学','65'),
('03','语文','84'),
('03','物理','70'),
('03','化学','76'),
('03','英语','54')

--使用UNION ALL来进行插入
insert into student
select '04','wangan','1895-5-27 14:30:28','女'
union all
select '05','zhangnan','1990-1-20 19:0:0','女'
go

---

---

--修改数据
update student set stuSex='男',stuAge='2016-5-9 8:0:0' where stuName='王男'
go

---

---

--删除数据
delete from student where stuNo=01
go

---

---

--存储过程查询所有数据
--begin...end 类似编程语言中的{}
create proc stu1
as
begin
select * from student;
end
go

exec stu1
go

---

---

--存储过程根据条件用户名查询用户信息
create proc stu2
@sname varchar(50) --声明全局变量
as
begin
select * from student s where s.stuName=@sname;
end
go

exec stu2 ''
go

---

---

--存储过程内部设定用户名查询用户信息
create proc stu3
@sname varchar(50)='王男'
as
begin
select * from student s where s.stuName=@sname;
end
go

exec stu3
go

---

---

--存储过程根据用户名查询是否存在这个用户信息
create proc stu4
@sname varchar(50),
@result varchar(8) output --输出参数
as
begin
if (select COUNT(1) from student s where s.stuName=@sname)>0
--if exists (select COUNT(1) from student s where s.stuName=@sname)
set br/>@result='存在!'
else
set br/>@result='不存在!'
end
go

declare @result varchar(8)
exec stu4 '王男',@result output
print @result
go

---

---

--存储过程内部设定局部变量用户名来查询用户信息
create proc stu5
as
declare @sname varchar(50) --局部变量声明
set @sname='杨幂'
begin
select * from student s where s.stuName=@sname
end
go

exec stu5
go

---

---

--存储过程根据条件用户学号查询用户名
create proc stu6
@stuNo varchar(50)
as
declare @sname varchar(50)
set @sname=(select s.stuName from student s where s.stuNo=@stuNo)
select @sname
go

exec stu6 '01'
go

---

---

--存储过程插入用户信息
create proc stu7
@stuNo varchar(50),
@stuName varchar(50),
@stuAge datetime,
@stuSex varchar(5)
as
begin
insert into student
(stuNo,stuName,stuAge,stuSex)
values
(@stuNo,@stuName,@stuAge,@stuSex)
end
go

exec stu7 '07','王莽','2000-9-9 9:9:9','女'
go

---

---

--存储过程根据用户名来删除对应的用户信息br/>--@@rowcount返回操作条数
--return返回信息，终止下面的操作
create proc stu8
@stuName varchar(50)
as
begin
delete from student where stuName=@stuName
return @@rowcount
end
go

declare @result varchar(50)
exec @result=stu8 '王莽'
select @result as '删除条数'
--print @result
go

---

---

--存储过程根据用户学号来查询他的平均分
create proc stu9
@stuNo varchar(50),
@avg int output
as
begin
set @avg=(select AVG(courseScore) from course where stuNo=@stuNo)
--等同
--select @avg=AVG(courseScore) from course where stuNo=@stuNo
end
go

declare @avg int
exec stu9 '02',@avg output
print @avg
go

---

---

--存储过程根据用户学号来联合查询用户信息和课程信息
create proc stu10
@stuNo varchar(50)
as
select c.stuNo,s.stuName,s.stuAge,s.stuSex,c.courseName,c.courseScore from student s join course c on s.stuNo=c.stuNo where s.stuNo=@stuNo
go

exec stu10 '02'
go

---

---

--存储过程判断学号是否存在，不存在，插入用户信息，返回消息；存在，返回信息
create proc stu11
@stuNo varchar(50),
@stuName varchar(50),
@stuAge datetime,
@stuSex varchar(5),
@result varchar(50) output
as
if exists (select * from student where stuNo=@stuNo)
begin
set @result='对不起，学号已存在!'
end
else
begin
insert into student
(stuNo,stuName,stuAge,stuSex)
values br/>(@stuNo,@stuName,@stuAge,@stuSex)
set @result='恭喜你，用户信息插入成功!'
end
go

declare @result varchar(50)
exec stu11 '06','王忠磊','1980-8-8 8:9:0','男',@result output
print @result

---

---

--存储过程查询当前用户的平均成绩与总的平均成绩之间的关系
create proc stu12
@stuNo varchar(50)
as
declare @curAvg decimal(18,2)
declare @totalAvg decimal(18,2)
if exists(select * from course where stuNo=@stuNo)
begin
set @totalAvg=(select AVG(courseScore) from course)
select @curAvg=AVG(courseScore) from course where stuNo=@stuNo
print ('总的平均分:'+convert(varchar(18),@totalAvg))
print ('该生的平均分:'+convert(varchar(18),@curAvg))
if @curAvg>@totalAvg
print '高于平均水平!'
else
print '低于平均水平!'
end
else
print '该生对应的分数信息不存在,请重新查询!'
go

exec stu12 '03'
go