休眠-TypedQuery.getResultList（）返回相同对象的列表

Question

这是对该问题的更多甚至更好的描述：

我做一个简单的选择查询。返回列表包含确切的记录/对象数，就好像我在数据库中进行相同的查询一样，但是问题在于所有对象都是相同/相同的。

例如，这是数据库中的结果（我删除了空值）：
26801 01-JAN-00 7 31-DEC-99 7 Obere Kirchstr。26 CH 8304 Walliselln
26801 01-JAN-00 2 31-DEC-99 2 Obere Kirchstr。26 CH 8304瓦利塞伦

这是变量地址的内容，正如我在执行查询后的调试过程中可以在Eclipse中看到的那样：

地址ArrayList（id = 81）
elementData对象[10]（id = 86）
[0] DLDBAddress（id = 82）
[1] DLDBAddress（id = 82）
[2] null
…
modCount 1
大小2

DLDBAddress [persid = 26801，valPeriodStart = 1900-01-01，valPeriodEnd =
9999-12-31，addressNr = 7，addressType = 7，addressRow1 = null，addressRow2 =
Obere Kirchstr。26，addressRow3 = null，country = CH，postalCode = 8304，city =
Walliselln，phoneNr = null，faxNr = null，sekretaryPhoneNr = null，alternatPhoneNr
= null，pagerNr = null]

DLDBAddress [persid = 26801，valPeriodStart = 1900-01-01，valPeriodEnd =
9999-12-31，addressNr = 7，addressType = 7，addressRow1 = null，addressRow2 =
Obere Kirchstr。26，addressRow3 = null，country = CH，postalCode = 8304，city =
Walliselln，phoneNr = null，faxNr = null，sekretaryPhoneNr = null，alternatPhoneNr
= null，pagerNr = null]]

如您所见，这两个对象是相同的。它们应该不同于addressNr和addressType …

这是我建立查询的代码片段：

public static <T> List<T> findBy(EntityManager eM, Class<T> boClass, String whereClause, String whereValue)  
 {
    EntityManager entityManager = eM;
    Query query = entityManager.createQuery("from " + boClass.getName() + " s where s." + whereClause + " = " + whereValue);
    ...
    return (List<T>) query.getResultList();
}

这是（非常简单的）结果查询：

来自ch.ethz.id.wai.pdb.bo.DLDBAddress，其中s.persid = 26801

这是生成的查询：

Hibernate: 
select
dldbaddres0_.PERSID as PERSID0_,
dldbaddres0_.ADRNUM as ADRNUM0_,
dldbaddres0_.ADRZEIL1 as ADRZEIL3_0_,
dldbaddres0_.ADRZEIL2 as ADRZEIL4_0_,
dldbaddres0_.ADRZEIL3 as ADRZEIL5_0_,
dldbaddres0_.ADRTYP as ADRTYP0_,
dldbaddres0_.ADRAUSWTEL as ADRAUSWTEL0_,
dldbaddres0_.ADRORT as ADRORT0_,
dldbaddres0_.ADRLAND as ADRLAND0_,
dldbaddres0_.ADRFAX as ADRFAX0_,
dldbaddres0_.ADRPSA as ADRPSA0_,
dldbaddres0_.ADRTEL as ADRTEL0_,
dldbaddres0_.ADRPLZ as ADRPLZ0_,
dldbaddres0_.ADRSEKTEL as ADRSEKTEL0_,
dldbaddres0_.BISDAT as BISDAT0_,
dldbaddres0_.VONDAT as VONDAT0_ 
from
NETHZ.V_DLDB_ADRESSE dldbaddres0_ 
where
dldbaddres0_.PERSID=26801

这里是实体：

@Entity
@Table(name = "V_DLDB_ADRESSE", schema="NETHZ")
public class DLDBAddress
{
  @Id
  @Column(name = "PERSID", insertable = false, updatable = false)
  private Integer   persid;
  @Temporal(TemporalType.DATE)
  @Column(name = "VONDAT", insertable = false, updatable = false)
  private Date   valPeriodStart;
  @Temporal(TemporalType.DATE)
  @Column(name = "BISDAT", insertable = false, updatable = false)
  private Date   valPeriodEnd;
  @Column(name = "ADRNUM", insertable = false, updatable = false)
  private Integer addressNr;
  @Column(name = "ADRTYP", insertable = false, updatable = false)
  private Integer addressType;
  @Column(name = "ADRZEIL1", insertable = false, updatable = false)
  private String addressRow1;
  @Column(name = "ADRZEIL2", insertable = false, updatable = false)
  private String addressRow2;
  @Column(name = "ADRZEIL3", insertable = false, updatable = false)
  private String addressRow3;
  @Column(name = "ADRLAND", insertable = false, updatable = false)
  private String country;
  @Column(name = "ADRPLZ", insertable = false, updatable = false)
  private String postalCode;
  @Column(name = "ADRORT", insertable = false, updatable = false)
  private String city;
  @Column(name = "ADRTEL", insertable = false, updatable = false)
  private String phoneNr;
  @Column(name = "ADRFAX", insertable = false, updatable = false)
  private String faxNr;
  @Column(name = "ADRSEKTEL", insertable = false, updatable = false)
  private String secretaryPhoneNr;
  @Column(name = "ADRAUSWTEL", insertable = false, updatable = false)
  private String alternatPhoneNr;
  @Column(name = "ADRPSA", insertable = false, updatable = false)
  private String pagerNr;

...

我想念什么吗？

啊，我正在连接到Oracle数据库。

在此先感谢Francesco

Answer 1

where dldbaddres0_.PERSID=26801

@Id
  @Column(name = "PERSID", insertable = false, updatable = false)

您将PERSID定义为@Id，这是一个主键。它对于您的应用程序来说真的很独特吗？从行为来看不是。但是对于希伯来说一定是。

那么会发生什么：

1. 您在数据库中有两个以上的记录，PERSID = 26801
2. 您查询他们WHERE PERSID = 26801
3. SQL查询返回两行以上
4. Hib将第一个加载并进入会话，并以PERSID作为键（因为它被标记为@Id）。对象被放入结果列表。
5. Hib加载第二个，注意会话中已经有一个具有相同@Id的对象，并将引用放入结果列表中。行数据将被忽略。
6. 这样就得到了两个以上的副本。