create table teacher ( sid number constraint teacher_sid_pk primary key, sname varchar2(20) constraint teacher_sname_notnull not null, email varchar2(64) constraint teacher_email_notnull not null constraint teacher_email_unique unique, sex number constraint teacher_sex_min_check check(sex in(1,2)), age number constraint teacher_age check(age>20) );
insert into teacher(sid, sname, email, sex, age) values (1, ‘tom11‘, ‘11@qq.com‘, 1, 21);
create table teacher2 ( sid number constraint teacher2_sid_pk primary key, sname varchar2(20) constraint teacher2_sname_notnull not null, email varchar2(64) constraint teache2r_email_notnull not null constraint teache2r_email_unique unique, sex number constraint teacher2_sex_min_check check(sex in(1,2)), age number constraint teacher2_age check(age>20), deptno number constraint teacher2_deptno_pk references dept(deptno) );
原文：https://www.cnblogs.com/wanghao-boke/p/13234991.html