oracle命令建立主键外键

oracle命令建立主键外键
 
1、创建一张学生表
[sql] 
SQL> create table t_stu(  
  2  stuid number(10) primary key,  
  3  stuname varchar2(20) not null,  
  4  stusex varchar2(2) default '男' check(stusex in('男','女')));  
   
Table created  
Executed in 0.547 seconds  
 
2、创建一张课程表
[sql] 
SQL> create table t_couse(  
  2  couseid number(10) primary key,  
  3  cousename varchar2(20) not null,  
  4  cousetype varchar2(4));  
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Table created  
Executed in 0.062 seconds  
 
3、创建一张学生课程成绩表（包括主外键）
[sql] 
SQL> create table t_score(  
  2  scoreid number(10) primary key,  
  3  stuid number(10) references t_stu(stuid),  
  4  couseid number(10),  
  5  constraint fk_couseid foreign key(couseid)  
  6  references t_couse(couseid)  
  7  on delete cascade);  
   
Table created