关于存储过程

Posted 2020-11-01

问题：使用存储过程有什么优缺点？什么时候使用存储过程？为什么使用存储过程？

1、存储过程有两种参数类型，输入（默认input），输出(output)

2、存储过程一个批执行——批（go）在Sql中起一个隔断作用

3、分页存储过程的使用：

（

　　1、变量的声明

）

--1
create procedure GetStudentsInfo
as
    select * from student
go


exec GetStudentsInfo

alter procedure GetStudentsInfo
as
    select * from student where stuSex = ‘男‘

exec GetStudentsInfo

--2
/*
public DataTable GetStudentsInfoByGrade(decimal mingrade, decimal maxgrade)
{}
*/

create proc GetStudentsInfoByGrade
    @mingrade numeric(3,1) = 60,
    @maxgrade numeric(3,1)
as
    select * from student where stuAvgrade >= @mingrade and stuAvgrade <= @maxgrade
go


--C#调用方法的对比：GetStudentsInfoByGrade(70,90)

exec GetStudentsInfoByGrade @maxgrade = 90
go

exec GetStudentsInfoByGrade 70,90
go

exec GetStudentsInfoByGrade @mingrade = 80,@maxgrade = 90
go

--3代输出(out)参数
/*
public void GetStuAvgradeTotalAndFemaleGradeTotal(out decimal stuTotal, out decimal stuFemaleTotal)
*/
--储存过程有两种参数类型一种是输入参数也是默认值input另一种是输出参数叫output 
create procedure GetStuAvgradeTotalAndFemaleGradeTotal
    @stuTotal real output,
    @stuFemaleTotal real output
As
    select @stuTotal = sum(stuAvgrade) from student;
    select @stuFemaleTotal = sum(stuAvgrade) from student
    where stuSex = ‘女‘
go

declare @total real, @femaleTotal real
exec GetStuAvgradeTotalAndFemaleGradeTotal @total output, @femaleTotal output;
select @total, @femaleTotal
go


--4修改和加密储存过程
alter procedure GetStudentsInfo with encryption
as
    select * from student
go

--5
create proc InsertStudent
    @stuId char(8),
    @stuName varchar(10),
    @stuSex  char(2),
    @stuBirth smalldatetime,
    @stuSpeciality varchar(50),
    @stuAvgrade numeric(3,1),    
    @stuDept  varchar(50) 
as
    insert into student values(@stuId,@stuName,@stuSex,@stuBirth,@stuSpeciality,@stuAvgrade,@stuDept)
go    


exec InsertStudent ‘20060214‘, ‘李刚‘,‘男‘,‘1987-07-01‘,‘网络工程‘,85.8,‘信息工程系‘   

select * from student