oracle,创建表

create table student1
(
sid number constraint student_pk primary key,
sname varchar2(20) constraint student_name_notnull not null,
gender varchar2(2) constraint student_gender check (gender in(‘男’,’女’)),
email varchar2(40) constraint studewnt_email_unique unique
constraint student_email_notnull not null,
deptno number constraint student_fk references dept(deptno) on delete set null
);
文字的形式没有颜色对比,不宜看,特上下图