Question

我在使用JPA的Oracle中有自动增量ID的问题。如果我使用这样的序列：

public class Customer {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO, generator = "customerSequence")
    @SequenceGenerator(name = "customerSequence", sequenceName = "CUSTOMER_SEQ")
    private int id;

    // getters and setters
}

我必须一直使用序列。例如，如果DBA不使用它并在执行这样的INSERT时提供实际的id值：

INSERT INTO CUSTOMER (ID, NAME) VALUES (1, 'Paul');
INSERT INTO CUSTOMER (ID, NAME) VALUES (2, 'John');
INSERT INTO CUSTOMER (ID, NAME) VALUES (3, 'Mark');
// bunch of other statements like this

然后序列值保持为0.所以CUSTOMER_SEQ.NEXTVAL返回实际已经在数据库中的1。

我需要获得灵活性的最佳方法。提供id时，序列应递增，以使数字不会发生冲突。

P.S。我尝试使用这样的触发器：

CREATE OR REPLACE 
TRIGGER CUSTOMER_INSERT
BEFORE INSERT ON "CUSTOMER"
FOR EACH ROW
DECLARE
  MAX_ID NUMBER;
  CURRENT_SEQ_VAL NUMBER;
BEGIN
  IF :NEW.ID IS NULL THEN
    SELECT CUSTOMER_SEQ.NEXTVAL INTO :NEW.ID FROM DUAL;
  ELSE
    SELECT GREATEST(NVL(MAX(ID), 0), :NEW.ID) INTO MAX_ID FROM "CUSTOMER";
    SELECT CUSTOMER_SEQ.NEXTVAL INTO CURRENT_SEQ_VAL FROM DUAL;
    WHILE CURRENT_SEQ_VAL < MAX_ID
    LOOP
      SELECT CUSTOMER_SEQ.NEXTVAL INTO CURRENT_SEQ_VAL FROM DUAL;
    END LOOP;
  END IF;
END;

当我使用原始SQL进行插入时，它工作正常，但是当我使用JPA时，有时候我会得到太大的id，有时会出现像这两样的奇怪错误：

ORA-04091: table CUSTOMER is mutating, trigger/function may not see it
ORA-04088: error during execution of trigger 'CUSTOMER_INSERT'

可能我在这里做错了什么。有人可以帮我找到解决方案吗？

自动增量最佳实践JPA Oracle DB

0 个答案: