8.存储过程和触发器

现在使用的数据库不再是之前的员工管理的数据库了，已经更改为学校上机实验使用的 学生成绩管理数据库，现附上生成学生成绩管理数据库的sql代码。使用该数据库，需要修改下路径。

USE [master]
GO
/****** Object:  Database [student]    Script Date: 2018/5/10 17:13:01 ******/
CREATE DATABASE [student]
 CONTAINMENT = NONE
 ON  PRIMARY 
( NAME = N'student', FILENAME = N'E:Program FilesMicrosoft SQL ServerMSSQL11.SQLEXPRESSMSSQLDATAstudent.mdf' , SIZE = 5120KB , MAXSIZE = UNLIMITED, FILEGROWTH = 1024KB )
 LOG ON 
( NAME = N'student_log', FILENAME = N'E:Program FilesMicrosoft SQL ServerMSSQL11.SQLEXPRESSMSSQLDATAstudent_log.ldf' , SIZE = 1024KB , MAXSIZE = 5120KB , FILEGROWTH = 10%)
GO
ALTER DATABASE [student] SET COMPATIBILITY_LEVEL = 110
GO
IF (1 = FULLTEXTSERVICEPROPERTY('IsFullTextInstalled'))
begin
EXEC [student].[dbo].[sp_fulltext_database] @action = 'enable'
end
GO
ALTER DATABASE [student] SET ANSI_NULL_DEFAULT OFF 
GO
ALTER DATABASE [student] SET ANSI_NULLS OFF 
GO
ALTER DATABASE [student] SET ANSI_PADDING OFF 
GO
ALTER DATABASE [student] SET ANSI_WARNINGS OFF 
GO
ALTER DATABASE [student] SET ARITHABORT OFF 
GO
ALTER DATABASE [student] SET AUTO_CLOSE OFF 
GO
ALTER DATABASE [student] SET AUTO_CREATE_STATISTICS ON 
GO
ALTER DATABASE [student] SET AUTO_SHRINK OFF 
GO
ALTER DATABASE [student] SET AUTO_UPDATE_STATISTICS ON 
GO
ALTER DATABASE [student] SET CURSOR_CLOSE_ON_COMMIT OFF 
GO
ALTER DATABASE [student] SET CURSOR_DEFAULT  GLOBAL 
GO
ALTER DATABASE [student] SET CONCAT_NULL_YIELDS_NULL OFF 
GO
ALTER DATABASE [student] SET NUMERIC_ROUNDABORT OFF 
GO
ALTER DATABASE [student] SET QUOTED_IDENTIFIER OFF 
GO
ALTER DATABASE [student] SET RECURSIVE_TRIGGERS OFF 
GO
ALTER DATABASE [student] SET  DISABLE_BROKER 
GO
ALTER DATABASE [student] SET AUTO_UPDATE_STATISTICS_ASYNC OFF 
GO
ALTER DATABASE [student] SET DATE_CORRELATION_OPTIMIZATION OFF 
GO
ALTER DATABASE [student] SET TRUSTWORTHY OFF 
GO
ALTER DATABASE [student] SET ALLOW_SNAPSHOT_ISOLATION OFF 
GO
ALTER DATABASE [student] SET PARAMETERIZATION SIMPLE 
GO
ALTER DATABASE [student] SET READ_COMMITTED_SNAPSHOT OFF 
GO
ALTER DATABASE [student] SET HONOR_BROKER_PRIORITY OFF 
GO
ALTER DATABASE [student] SET RECOVERY SIMPLE 
GO
ALTER DATABASE [student] SET  MULTI_USER 
GO
ALTER DATABASE [student] SET PAGE_VERIFY CHECKSUM  
GO
ALTER DATABASE [student] SET DB_CHAINING OFF 
GO
ALTER DATABASE [student] SET FILESTREAM( NON_TRANSACTED_ACCESS = OFF ) 
GO
ALTER DATABASE [student] SET TARGET_RECOVERY_TIME = 0 SECONDS 
GO
USE [student]
GO
/****** Object:  Table [dbo].[course]    Script Date: 2018/5/10 17:13:02 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[course](
	[cno] [nchar](10) NULL,
	[cname] [nchar](10) NULL,
	[credit] [nchar](10) NULL,
	[pcno] [nchar](10) NULL
) ON [PRIMARY]

GO
/****** Object:  Table [dbo].[sc]    Script Date: 2018/5/10 17:13:02 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[sc](
	[sno] [nchar](10) NULL,
	[cno] [nchar](10) NULL,
	[grade] [int] NULL
) ON [PRIMARY]

GO
/****** Object:  Table [dbo].[student]    Script Date: 2018/5/10 17:13:02 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[student](
	[sno] [nchar](10) NULL,
	[sname] [nchar](10) NULL,
	[ssex] [nchar](10) NULL,
	[sage] [nchar](10) NULL,
	[sdept] [nchar](10) NULL
) ON [PRIMARY]

GO
INSERT [dbo].[course] ([cno], [cname], [credit], [pcno]) VALUES (N'1         ', N'数据库       ', N'4         ', N'5         ')
INSERT [dbo].[course] ([cno], [cname], [credit], [pcno]) VALUES (N'2         ', N'数学        ', N'6         ', NULL)
INSERT [dbo].[course] ([cno], [cname], [credit], [pcno]) VALUES (N'3         ', N'信息系统      ', N'3         ', N'1         ')
INSERT [dbo].[course] ([cno], [cname], [credit], [pcno]) VALUES (N'4         ', N'操作系统      ', N'4         ', N'6         ')
INSERT [dbo].[course] ([cno], [cname], [credit], [pcno]) VALUES (N'5         ', N'数据结构      ', N'4         ', N'7         ')
INSERT [dbo].[course] ([cno], [cname], [credit], [pcno]) VALUES (N'6         ', N'数据处理      ', N'3         ', NULL)
INSERT [dbo].[course] ([cno], [cname], [credit], [pcno]) VALUES (N'7         ', N'Pascal    ', N'4         ', N'6         ')
INSERT [dbo].[sc] ([sno], [cno], [grade]) VALUES (N'95001     ', N'1         ', 92)
INSERT [dbo].[sc] ([sno], [cno], [grade]) VALUES (N'95001     ', N'2         ', 85)
INSERT [dbo].[sc] ([sno], [cno], [grade]) VALUES (N'95001     ', N'3         ', 88)
INSERT [dbo].[sc] ([sno], [cno], [grade]) VALUES (N'95002     ', N'2         ', 90)
INSERT [dbo].[sc] ([sno], [cno], [grade]) VALUES (N'95002     ', N'3         ', 80)
INSERT [dbo].[sc] ([sno], [cno], [grade]) VALUES (N'95003     ', N'2         ', 85)
INSERT [dbo].[sc] ([sno], [cno], [grade]) VALUES (N'95004     ', N'1         ', 58)
INSERT [dbo].[sc] ([sno], [cno], [grade]) VALUES (N'95004     ', N'2         ', 85)
INSERT [dbo].[student] ([sno], [sname], [ssex], [sage], [sdept]) VALUES (N'95001     ', N'李勇        ', N'男         ', N'20        ', N'cs        ')
INSERT [dbo].[student] ([sno], [sname], [ssex], [sage], [sdept]) VALUES (N'95002     ', N'刘晨        ', N'女         ', N'19        ', N'is        ')
INSERT [dbo].[student] ([sno], [sname], [ssex], [sage], [sdept]) VALUES (N'95003     ', N'王敏        ', N'女         ', N'18        ', N'ma        ')
INSERT [dbo].[student] ([sno], [sname], [ssex], [sage], [sdept]) VALUES (N'95004     ', N'张立        ', N'男         ', N'19        ', N'is        ')
INSERT [dbo].[student] ([sno], [sname], [ssex], [sage], [sdept]) VALUES (N'95005     ', N'流云        ', N'女         ', N'18        ', N'cs        ')
USE [master]
GO
ALTER DATABASE [student] SET  READ_WRITE GO

现在进入存储过程，之前的代码未保存，已经丢失，这里不重新写了，直接附上一个简单的带有输入参数的存储过程。

--带有输入参数的存储过程
create procedure ssc
 @cno char(5)
 as
 select student.sno,sname,grade
 from student join sc on student.sno=sc.sno
 where sc.cno=@cno
 
 execute ssc '3'

接下来是触发器，触发器的功能是：向sc表中插入一行数据，这是检查对应的课程是否正在准备中（查看对应课程表再表course中的状态是否为1），如果在准备中，则不能选修。（需要提前向course表中 插入一列status(char(1))）

step1:创建触发器

create trigger scinsert
on sc
after insert
as
if(select status from course,inserted where course.cno=inserted.cno)='1'
begin
print '该课程正在准备中'
print '该次选课操作失败'
rollback transaction
end

step2:插入一行状态为1的数据（在准备中）

insert into course (cno,cname,status)
values('00010','界面设计','1')

step3:向sc表中插入课程号正在准备的数据

insert into sc(sno,cno) values ('03001','00010')

step4:更新course表中的status，重新执行step3

update course 
set status='0'
where cno='00010'