Sstudent表

Course表

SC表

student 表

create table student

(

sno char()     primary key,

sname char()    not null,

Ssex char()    check( Ssex in('男','女')),

Sage smallint    check(Sage between  and ),

Sdept char()

)   

insert into student values('','李勇','男',,'CS')

insert into student values('','刘晨','女',,'CS')

insert into student values('','王敏','女',,'MA')

insert into student values('','张立','男',,'IS')

course表

create table course

(

 cno char() ,    --primary key

cname char(),

Cpno char(),

Ccredit smallint,

constraint cPK primary key(cno),

 constraint cFK foreign key(Cpno) references course(cno)

)  

insert into course values('','数据库',null,)

insert into course values('','数学',null,)

insert into course values('','信息系统',null,)

insert into course values('','操作系统',null,)

insert into course values('','数据结构',null,)

insert into course values('','数据处理',null,)

insert into course values('','PASCAL语言',null,)

update course set cpno='' where cno=''

update course set cpno='' where cno=''

update course set cpno='' where cno=''

update course set cpno='' where cno=''

update course set cpno=''where cno=''

select * from course

sc 表  完整约束命名子 句----约束名称不能 重复

________________________________________

create table sc

(

sno char() not null,

cno char() not null,

grade smallint check(grade>= and grade<=),

constraint sPK primary key(sno,cno),

constraint sFK foreign key(sno) references student(sno) on delete cascade

                                                        on update cascade,

constraint sFK foreign key(cno) references course(cno) on delete no action

                                                       on update  cascade

)      

sc 表

create table sc

(

sno char() not null,

cno char() not null,

grade smallint check(grade>= and grade<=),

constraint sPK primary key(sno,cno),

constraint sFK1 foreign key(sno) references student(sno) on delete cascade

                                                        on update cascade,

constraint sFK2 foreign key(cno) references course(cno) on delete no action

                                                       on update  cascade

)      

sc表.note

________________________________________

create table sc

(  sno char(),

   cno char(),

   grade smallint,

primary key(sno, cno),

foreign key(sno) references student(sno),

foreign key(cno) references course(cno)

)