oracle建表设置主键自增

create table member(
memberId number primary key,
memberMail varchar2(20)not null,
memberName varchar2(20) not null,
memberPassword varchar2(20)
);

CREATE SEQUENCE emp_sequence
INCREMENT BY 1 -- 每次加几个
START WITH 1 -- 从1开始计数
NOMAXVALUE -- 不设置最大值
NOCYCLE -- 一直累加，不循环
NOCACHE -- 不建缓冲区

create trigger mem_trig before
insert on member for each row when (new.memberId is null)
begin

 select emp_sequence.nextval into:new.memberId from dual;

 end;

insert into member(memberMail,memberName,memberPassword) values('123@qq.com','jack','123456');

select * from member;