oracle 创建主键自动增长

/******* 创建短信主键自增   *************/


create sequence msm_sequence
minvalue 1       
nomaxvalue       
start with 1     
increment by 1   
nocycle           
nocache;         






CREATE OR REPLACE TRIGGER  tr_msm_sequence
BEFORE
insert on NET_SMS_EXCHANG
for each row
begin
select msm_sequence.nextval into :NEW.SMS_EXCHANG_UUID from dual;
end;