ORACLE 创建主键

//创建主键//创建序列//创建触发器//执行OK
alter table question add constraints pk_question primary key(id);
CREATE SEQUENCE question_seq INCREMENT BY 1 START WITH 1 NOMAXVALUE NOCYCLE NOCACHE;

CREATE OR REPLACE TRIGGER question_trig_autoinc
BEFORE INSERT ON question
FOR EACH ROW
BEGIN
  SELECT question_seq.nextval INTO :new.id  FROM DUAL;
END;
/