create sequence S_USER;
/

create trigger tib_USER before insert on USER for each row declare integrity_error exception;
    errno            integer;
    errmsg           char(200);
    dummy            integer;
    found            boolean;

 begin -- Column id uses sequence S_USER select S_USER.NEXTVAL INTO :new.objectid from dual;

-- Errors handling
exception
    when integrity_error then
       raise_application_error(errno,errmsg);
end;
/

有几个地方注意，先创建序列create sequence S_USER。 再创建触发器，创建触发器的时候： select S_USER.NEXTVAL INTO :new.objectid from dual; new.objectid，objectid就是自增字段