数据库作业14：第五章： 数据库完整性 习题 + 存储过程

（1）

	CREATE TABLE 部门
	(
		部门号 CHAR(12) PRIMARY KEY,
		名称 CHAR(4),
		经理名 CHAR(4),
		电话 CHAR(10)
	);
	
	CREATE TABLE 职工
	(
		职工号 CHAR(12) PRIMARY KEY,
		姓名 CHAR(4),
		年龄 SMALLINT CHECK(年龄<=60),
		职务 CHAR(2),
		工资 SMALLINT,
		部门号 CHAR(12),
		FOREIGN KEY (部门号) REFERENCES 部门(部门号)
	);
	

（1）

	--在SC表中添加相应离散数学学生的信息
	INSERT INTO Course VALUES(9,'离散',NULL,2);
	
	INSERT INTO SC VALUES('20121512',9,12);
	INSERT INTO SC VALUES('201215122',9,22);
	INSERT INTO SC VALUES('201215123',9,32);
	INSERT INTO SC VALUES('201215125',9,42);
	INSERT INTO SC VALUES('201215128',9,52);
	INSERT INTO SC VALUES('201515129',9,62);
	INSERT INTO SC VALUES('201515131',9,72);
	INSERT INTO SC VALUES('201515132',9,82);
	INSERT INTO SC VALUES('201515133',9,92);

	--建立分段统计表
	DROP TABLE IF EXISTS Section;
	CREATE TABLE Section
	(
		grade CHAR(10),     /*成绩分段*/
		num INT        /*人数*/
	);

	INSERT INTO Section VALUES('0-20',NULL);
	INSERT INTO Section VALUES('21-40',NULL);
	INSERT INTO Section VALUES('41-60',NULL);
	INSERT INTO Section VALUES('61-80',NULL);
	INSERT INTO Section VALUES('81-10',NULL);

--建立分段统计的存储过程
	IF (exists (select * from sys.objects where name = 'Sec_statistics'))
	    DROP PROCEDURE Sec_statistics
	GO
	CREATE PROCEDURE Sec_statistics

	AS
		DECLARE   /*定义变量*/
		@20Num SMALLINT,
		@40Num SMALLINT,
		@60Num SMALLINT,
		@80Num SMALLINT,
		@100Num SMALLINT,      /*各分数段的人数*/
		@Cno char(4);        /*课程号*/
		
			SELECT @Cno=Cno     /*离散的课程号*/
			FROM Course
			WHERE Cname='离散';
			
			SELECT @20Num=count(*)   /*筛选出相应的信息*/
			FROM SC
			WHERE Cno=@Cno AND Grade<=20 AND Grade>0;
			
			SELECT @40Num=count(*)
			FROM SC
			WHERE Cno=@Cno AND Grade<=40 AND Grade>20;
			
			SELECT @60Num=count(*)
			FROM SC
			WHERE Cno=@Cno AND Grade<=60 AND Grade>40;

			SELECT @80Num=count(*)
			FROM SC
			WHERE Cno=@Cno AND Grade<=80 AND Grade>60;
	
			SELECT @100Num=count(*)
			FROM SC
			WHERE Cno=@Cno AND Grade<=100 AND Grade>80;
	
	/*将各分段数量填入表中*/
		INSERT INTO Section VALUES('0-20',@20Num);
		INSERT INTO Section VALUES('21-40',@40Num);
		INSERT INTO Section VALUES('41-60',@60Num);
		INSERT INTO Section VALUES('61-80',@80Num);
		INSERT INTO Section VALUES('81-10',@100Num);
	

		EXEC Sec_statistics
		SELECT *
		FROM Section

（2）

	/*建立平均成绩表*/
	DROP TABLE IF EXISTS Avggrade;
	CREATE TABLE Avggrade
	(
		Cno CHAR(10),
		Avg FLOAT
	); 
	

	IF (exists (select * from sys.objects where name = 'Avg'))
	    DROP PROCEDURE Avg
	GO
	CREATE PROCEDURE Avg
	AS
		DECLARE 
		@AVG1 FLOAT,
		@AVG2 FLOAT,
		@AVG3 FLOAT,
		@AVG4 FLOAT,
		@AVG5 FLOAT;
		
		SELECT @AVG1=AVG(Grade)
		FROM SC
		WHERE Cno=1;

		SELECT @AVG2=AVG(Grade)
		FROM SC
		WHERE Cno=6;
		
		SELECT @AVG3=AVG(Grade)
		FROM SC
		WHERE Cno=3;
		
		SELECT @AVG4=AVG(Grade)
		FROM SC
		WHERE Cno=4;
		
		SELECT @AVG5=AVG(Grade)
		FROM SC
		WHERE Cno=5;
		
		INSERT INTO Avggrade VALUES(1,@AVG1);
		INSERT INTO  Avggrade VALUES(6,@AVG2);
		INSERT INTO  Avggrade VALUES(3,@AVG3);
		INSERT INTO  Avggrade VALUES(4,@AVG4);
		INSERT INTO  Avggrade VALUES(5,@AVG5);

		EXEC Avg
		SELECT *
		FROM Avggrade;

（3）

/*添加一列*/
	ALTER TABLE SC ADD Rank CHAR(2);
	
	IF (exists (select * from sys.objects where name = 'Update'))
	    DROP PROCEDURE Update
	GO
	CREATE PROCEDURE Update
	AS
	 	UPDATE SC SET Rank='E' WHERE Grade<=20;
	 	UPDATE SC SET Rank='D' WHERE Grade>20 AND Grade<=40;
	 	UPDATE SC SET Rank='C' WHERE Grade>40 AND Grade<=60;
	 	UPDATE SC SET Rank='C' WHERE Grade>60 AND Grade<=80;
	 	UPDATE SC SET Rank='A' WHERE Grade>80 AND Grade<=100;

	EXEC Up
	SELECT *
	FROM SC

到这一步的时候，运行语句，就报了一行错，第一行有个什么过程SC_T,第二行说是对象SC_U不存在。
然后我就到处看了看，删了个SC里的触发器SC_T，然后就行了。（其实我也不知道咋回事）