CREATE SEQUENCE USERID INCREMENT BY 1 START WITH 1 MAXVALUE 1.0E28 MINVALUE 1 NOCYCLE NOCACHE NOORDER; CREATE OR REPLACE TRIGGER USERADD BEFORE INSERT ON MEMBERRG FOR EACH ROW BEGIN SELECT LPAD(USERID.NEXTVAL,4,'0') INTO :NEW.NUM FROM DUAL; END;
create sequence student_sequence start with 10000; insert into students(id,fisrname) values(students_sequence.NEXTVAL,'Scott')select student_sequence.CURRVAL "seqvalue" from dual;(得到单前的sequence)
建立一个最小为1,最大为999999999的一个序列号会自动循环的序列create sequence 序列名 increment by 1 start with 1 maxvalue 999999999 cycle;当向表中插入数据时,SQL语句写法如下:SQL> insert into 表名 values(序列名.nextval,列1值,列2值);
MAXVALUE 1.0E28 MINVALUE 1 NOCYCLE
NOCACHE NOORDER;
CREATE OR REPLACE TRIGGER USERADD
BEFORE INSERT ON MEMBERRG
FOR EACH ROW
BEGIN
SELECT LPAD(USERID.NEXTVAL,4,'0') INTO :NEW.NUM FROM DUAL;
END;
start with 10000;
insert into students(id,fisrname)
values(students_sequence.NEXTVAL,'Scott')select student_sequence.CURRVAL "seqvalue"
from dual;(得到单前的sequence)
increment by 1
start with 1
maxvalue 999999999
cycle;当向表中插入数据时,SQL语句写法如下:SQL> insert into 表名 values(序列名.nextval,列1值,列2值);
建一个触发器