sql> create table staff (
  2    emp_id number primary key,3    staff_name varchar2(100)
  4  );

Table created.

sql> create sequence emp_id_seq;

Sequence created.

现在,您可以创建一个使用序列来填充主键的触发器

sql> create trigger trg_emp_id
  2    before insert on staff
  3    for each row
  4  begin
  5    select emp_id_seq.nextval
  6      into :new.emp_id
  7      from dual;
  8  end;
  9  /

Trigger created.

现在,当您插入数据时,您不需要指定EMP_ID列 – 它将自动由触发器填充

sql> insert into staff( staff_name ) values ('Justin');

1 row created.

sql> select * from staff;

    EMP_ID STAFF_NAME
---------- --------------------
         1 Justin