基本的SQL语句

  • Z时代
  • 2024-01-10
  • 分类：综合

database

表结构




实验内容

1

  • 用SQL语句创建数据库CAP，数据文件名为CAPData.mdf，数据文件的初始存储空间大小为50M，最大存储空间为500M，存储空间自动增长量为10M。

CREATE DATABASE CAP
ON
(
	NAME = CAP,
	FILENAME = "C:UserseroDesktopCAPData.mdf", -- 文件名
	SIZE = 50, -- 初始存储空间大小
	MAXSIZE = 500,  -- 最大存储空间大小
	FILEGROWTH = 10  -- 自动增长量
)

2

  • 在CAP数据库中用SQL语句创建下面的4张表，合理设计每个字段的数据类型，建立主键与外键约束。表Products中的Price字段不允许为空。表Customers的discnt字段取值范围在[0,30]之间。利用SQL语句向表中添加表结构中的数据。

use CAP
CREATE TABLE Customers
(
	"cid" char(4) CONSTRAINT Custom_Prim PRIMARY KEY,
	"cname" varchar(10),
	"city" varchar(10),
	"discnt" numeric(4,2) CONSTRAINT DISCNT_CHK CHECK(discnt BETWEEN 0 AND 30)
)
CREATE TABLE Products
(
	"Pid" char(3) CONSTRAINT Product_Prim PRIMARY KEY,
	"pname" varchar(10),
	"city" varchar(10),
	"quantity" int,
	"price" numeric(10,2) CONSTRAINT Price_NotNull NOT NULL
)
CREATE TABLE Agents
(
	"Aid" char(3) CONSTRAINT Agent_Prim PRIMARY KEY,
	"aname" varchar(10),
	"city" varchar(10),
	"percent" TINYINT
)
CREATE TABLE Orders
(
	"OrDno" char(4) CONSTRAINT Order_Prim PRIMARY KEY,
	"month" char(3) CONSTRAINT Month_CHK CHECK(month in ("Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec") ),
	"cid" char(4) CONSTRAINT Cid_Fore FOREIGN KEY REFERENCES Customers(cid),
	"aid" char(3) CONSTRAINT Aid_Fore FOREIGN KEY REFERENCES Agents(Aid),
	"pid" char(3) CONSTRAINT Pid_Fore FOREIGN KEY REFERENCES Products(Pid),
	"qty" int,
	"dollars" numeric(10,2)
)

3

  • 利用系统预定义的存储过程sp_helpdb查看数据库的相关信息，例如所有者、大小、创建日期等。

EXEC sp_helpdb

4

  • 利用系统预定义的存储过程sp_helpconstraint查看表中出现的约束（包括Primary key, Foreign key, check constraint, default, unique）。

EXEC sp_helpconstraint Orders

5

  • 创建一张表Orders_Jan，表的结构与Orders相同，将Orders表中month为‘Jan’的订单记录复制到表Orders_Jan中。

CREATE TABLE Orders_Jan
(
	"OrDno" char(4) CONSTRAINT Order_Jan_Prim PRIMARY KEY,
	"month" char(3) ,
	"cid" char(4) CONSTRAINT Jan_Cid_Fore FOREIGN KEY REFERENCES Customers(cid),
	"aid" char(3) CONSTRAINT Jan_Aid_Fore FOREIGN KEY REFERENCES Agents(Aid),
	"pid" char(3) CONSTRAINT Jan_Pid_Fore FOREIGN KEY REFERENCES Products(Pid),
	"qty" int,
	"dollars" numeric(10,2)
);
INSERT INTO Orders_Jan
SELECT * 
FROM Orders
WHERE month="Jan"

6

  • 将Orders表中month为‘Jan’的订单记录全部删掉。

DELETE 
FROM Orders
WHERE month="Jan"

7

  • 对曾经下过金额（dollars）大于500的订单的客户，将其discnt值增加2个百分点（+2）。

UPDATE Customers
SET  discnt = discnt + 2  -- 更新discnt
WHERE cid IN(			-- 找出下过500订单的客户cid
			SELECT DISTINCT cid -- 使用DISTINCT防止对同一个客户重复更新discnt
            -- 其实可以直接SELECT cid , IN会自动去除重复值
			FROM Orders
			WHERE dollars > 500
			)

8

  • 写一段TSQL程序，向表Orders中增加5000条记录，要求订单尽可能均匀地分布在12个月中。

use CAP
DECLARE @i AS INT,@randNum AS FLOAT,@mon AS char(3),@OrdNo AS SMALLINT,@cid AS char(4),@aid AS char(3),@pid AS char(3),@price AS numeric(10,2);
SET @i=1;
SET @OrdNo=1030;
while @i<=5000  -- 流程控制，循环5000次
	BEGIN
		SET @randNum=RAND()*12;
		SET @mon=							-- 随机产生月份
		CASE
			WHEN @randNum<1 THEN "Jan"
			WHEN @randNum>=1 AND @randNum<2 THEN "Feb"
			WHEN @randNum>=2 AND @randNum<3 THEN "Mar"
			WHEN @randNum>=3 AND @randNum<4 THEN "Apr"
			WHEN @randNum>=4 AND @randNum<5 THEN "May"
			WHEN @randNum>=5 AND @randNum<6 THEN "Jun"
			WHEN @randNum>=6 AND @randNum<7 THEN "Jul"
			WHEN @randNum>=7 AND @randNum<8 THEN "Aug"
			WHEN @randNum>=8 AND @randNum<9 THEN "Sep"
			WHEN @randNum>=9 AND @randNum<10 THEN "Oct"
			WHEN @randNum>=10 AND @randNum<11 THEN "Nov"
			ELSE "Dec"
		END
		SELECT  @cid=cid 	-- 随机获取一个用户id
		FROM Customers
		ORDER BY NEWID()
		SELECT @pid=Pid,@price=price	-- 随机获取一个产品id以及对应的产品价格
		FROM Products
		ORDER BY NEWID()
		SET @aid=(SELECT TOP 1 Aid 			-- 随机获取一个代理商id
				  FROM Agents
		          ORDER BY NEWID()
				  )
		SET @randNum=RAND()*2000+400;  -- 生成400至2400的随机订单数
		INSERT INTO Orders				-- 插入一条订单记录
		VALUES(CONVERT(char(4),@OrdNo),@mon,@cid,@aid,@pid,CONVERT(INT,@randNum),CONVERT(INT,@randNum) * @price);
        -- 使用转换函数CONVERT()
		SET @OrdNo=@OrdNo+1;
		SET @i=@i+1;
	END

9

  • 在表Orders的’month’字段上建立索引。

CREATE INDEX Orders_Index
ON Orders(month)

10

  • 创建一个视图order_month_summary，视图中的字段包括月份、该月的订单总量和该月的订单总金额。基于视图order_month_summary，查询第一季度各个月份的订单总量和订单总金额。

CREATE VIEW order_month_summary(month,total_qty,total_dollars)
AS SELECT month,SUM(qty),SUM(dollars)      -- 获得每月的总订单，总金额
   FROM Orders
   GROUP BY month

SELECT month,total_qty,total_dollars
FROM order_month_summary
WHERE month IN ("Jan","Feb","Mar")     -- 查询第一季度

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