CREATE SEQUENCE [INCREMENT BY n][START WITH n][{MAXVALUE/ MINVALUE n|NOMAXVALUE}][{CYCLE|NOCYCLE}][{CACHE n|NOCACHE}];

-- Create sequence        create sequence SEQ_T_RECV        increment by 1        start with 1        maxvalue 9999999        nomaxvalue nocycle nocache;

-- Create table        create table RECV_MSG (            id NUMBER,            messageid VARCHAR2(32),            contents VARCHAR2(2000),            app_flg VARCHAR2(100),            phonenumber VARCHAR2(2000),            updatetime DATE default sysdate        );

CREATE OR REPLACE TRIGGER "recv_trig"         BEFORE INSERT ON recv_msg        REFERENCING OLD AS OLD NEW AS NEW FOR EACH ROW        DECLARE            BEGIN                SELECT SEQ_T_RECV.NEXTVAL INTO :NEW.ID FROM DUAL;            END        recv_trig;

insert into test values(seq_on_test.nextval,'Mary',15);        insert into test values(seq_on_test.nextval,'Tom',16);

select * from test; -- /* 1 Mary 15 2 Tom 16 */

select seq_on_test.currval from dual;        select seq_on_test.nextval from dual; -- /* 2 3 */