SQL 建立数据库、表 && 表中增删数据项

我们这节课的任务是：
王珊老师《数据库系统概论（5）》第三章习题4,5,9。
以下代码来自第4题

1.建库建表：

--drop table S    --删除表S
Create database SQLTest4

Create table S (
	SNO CHAR(5),
	SNAME CHAR(8),
	STATUS INT,
	CITY CHAR(6)
)

Create table P (
	PNO CHAR(5),
	PNAME CHAR(8),
	COLOR CHAR(5),
	WEIGHT INT
)

Create table J (
	JNO CHAR(5),
	JNAME CHAR(20),	
	CITY CHAR(6)
)

Create table SPJ (
	SNO char(5),
	PNO char(5),
	JNO char(5),
	QTY int
)

2.表中增添/删除数据项

Delete from S WHERE sno='S1'
Insert into S values('S1','精益',20,'天津')
Insert into S values('S2','盛锡',10,'北京')
Insert into S values('S3','东方红',30,'北京')
Insert into S values('S4','丰泰盛',20,'天津')
Insert into S values('S5','为民',30,'上海')

Insert into P values('P1','螺母','红',20)
Insert into P values('P2','螺栓','绿',10)
Insert into P values('P3','螺丝刀','蓝',30)
Insert into P values('P4','螺丝刀','红',20)
Insert into P values('P5','凸轮','蓝',30)
Insert into P values('P6','齿轮','红',30)


Insert into J values('J1','三建','北京')
Insert into J values('J2','一汽','长春')
Insert into J values('J3','弹簧厂','天津')
Insert into J values('J4','造船厂','天津')
Insert into J values('J5','机车厂','唐山')
Insert into J values('J6','无线电厂','常州')
Insert into J values('J7','半导体厂','南京')


Insert into SPJ values('S1','P1','J1','200')
Insert into SPJ values('S1','P1','J3','100')
Insert into SPJ values('S1','P1','J4','700')
Insert into SPJ values('S1','P2','J2','100')

Insert into SPJ values('S2','P3','J1','400')
Insert into SPJ values('S2','P3','J2','200')
Insert into SPJ values('S2','P3','J4','500')
Insert into SPJ values('S2','P5','J5','400')
Insert into SPJ values('S2','P5','J1','400')

Insert into SPJ values('S3','P1','J1','200')
Insert into SPJ values('S3','P3','J1','200')

Insert into SPJ values('S4','P5','J1','100')
Insert into SPJ values('S4','P6','J3','300')
Insert into SPJ values('S4','P6','J4','200')

Insert into SPJ values('S5','P2','J4','100')
Insert into SPJ values('S5','P3','J1','200')
Insert into SPJ values('S5','P6','J2','200')
Insert into SPJ values('S5','P6','J4','500')