具有空值的 JPA 复合主键

我有一个表，其中包含 oracle 数据库中的客户数据。下面是一个简化的定义：

CUSTOMER (CUSTOMER_ID NUMBER NOT NULL,
          SOURCE_SYSTEM VARCHAR2(30),
          FULL_NAME VARCHAR2(360),
          PHONE_NUMBER VARCHAR2(240)
          )

此表的主键是 。(CUSTOMER_ID, SOURCE_SYSTEM)

该表具有许多行，其为 null。在数据库级别，没有问题，但是当我尝试通过JPA实体访问这些行中的任何一个时，它会导致许多问题：SOURCE_SYSTEM

1：使用以 null 读取行始终会导致返回 null。em.find()SOURCE_SYSTEM

2：如果表中不存在记录，则使用空值的行进行更新插入会成功，但在后续更新时会失败，因为合并始终会导致运行插入。em.merge()SOURCE_SYSTEM

3：用于显式查询具有 null 的行会导致以下异常：em.createQuery()

Exception [EclipseLink-6044] (Eclipse Persistence Services - 2.3.1.v20111018-r10243):
   org.eclipse.persistence.exceptions.QueryException
Exception Description: The primary key read from the row [ArrayRecord(
CUSTOMER.CUSTOMER_ID => 1
CUSTOMER.FULL_NAME => GUY PERSON
CUSTOMER.PHONE_NUMBER => 555-555-1234
CUSTOMER.SOURCE_SYSTEM => null)] during the execution of the query was detected to be null.
   Primary keys must not contain null.
Query: ReadAllQuery(referenceClass=Customer sql="SELECT CUSTOMER_ID, FULL_NAME, PHONE_NUMBER, SOURCE_SYSTEM FROM CUSTOMER WHERE ((CUSTOMER_ID = ?) AND (SOURCE_SYSTEM IS NULL))")

不幸的是，“主键不能包含空值”似乎是非常最终的。我无法找到太多有关此错误的解决方法的信息，这使得似乎没有解决方案。

问题：我想知道是否有人有任何基于Java代码的解决方案，不涉及对数据库进行更改。我目前的解决方法是用作表的，但这意味着我不能再使用 或 。ROW_ID@Idem.merge()em.find()

以下是我的 Java 类：

客户.java：

@Entity
@Table(name = "CUSTOMER")
public class Customer implements Serializable {
  private static final long serialVersionUID = 1L;

  @EmbeddedId
  private Customer_Id key;

  @Column(name = "CUSTOMER_ID", nullable = false, insertable = false, updatable = false)
  private Long customerId;
  @Column(name = "SOURCE_SYSTEM", length = 30, insertable = false, updatable = false)
  private String sourceSystem;

  @Column(name = "FULL_NAME", length = 360)
  private String fullName;
  @Column(name = "PHONE_NUMBER", length = 240)
  private String phoneNumber;

  //Setters, Getters, etc
  ...
}

Customer_Id.java

@Embeddable
public class Customer_Id implements Serializable {
  private static final long serialVersionUID = 1L;

  @Column(name = "CUSTOMER_ID", nullable = false)
  private Long customerId;
  @Column(name = "SOURCE_SYSTEM", length = 30)
  private String sourceSystem;

  //Setters, Getters, etc
  ...
}