Oracle 序列+触发器

Oracle 序列+触发器

删除序列

DROP IAM_USER_PUSH_ID_SEQ;

添加序列

CREATE SEQUENCE  "IAM_USER_PUSH_ID_SEQ"  INCREMENT BY 1 MINVALUE 1 MAXVALUE 999999999999999999999999 CYCLE NOCACHE ORDER ;

触发器 -简单

create or replace trigger IAM_USER_PUSH_ID_TRI 
before insert on IAM_USER_PUSH
for each row 
begin 
select IAM_USER_PUSH_ID_SEQ.nextval into :new.id from dual; 
end;

触发器-如果存在会替换

CREATE OR REPLACE TRIGGER "IAM_USER_PUSH_ID_TRI" BEFORE INSERT OR UPDATE ON IAM_USER_PUSH
FOR EACH ROW
DECLARE
v_count NUMBER(24) :=0;
v_newVal NUMBER(24) := 0;
BEGIN
  IF INSERTING AND :new.id IS NULL THEN
    SELECT  IAM_USER_PUSH_ID_SEQ.NEXTVAL INTO v_newVal FROM DUAL;
    -- If this is the first time this table have been inserted into (sequence == 1)
    SELECT COUNT(1) INTO v_count FROM IAM_USER_PUSH WHERE ID = v_newVal;
    IF(v_count <> 0) THEN
      LOOP
           EXIT WHEN v_count = 0;
           SELECT IAM_USER_PUSH_ID_SEQ.nextval INTO v_newVal FROM dual;
         SELECT COUNT(1) INTO v_count FROM IAM_USER_PUSH WHERE ID = v_newVal;
      END LOOP;
    END IF;
   -- assign the value from the sequence to emulate the identity column
   :new.id := v_newVal;
  END IF;
END;