主键字段的Oracle序列不会检索Hibernate中当前插入的值 [英] Oracle sequence for a primary key field doesn't retrieve the currently inserted value in Hibernate

问题描述

我有以下代码试图为 COUNTRY 的主键列 COUNTRY_ID 提取生成的序列值>表在我的Oracle（10g）数据库中。

  Country c = new Country（）; 
 
 c.setCountryName（request.getParameter（txtCountryName））; 
 c.setCountryCode（request.getParameter（txtCountryCode））; 
 Zone z =（Zone）session.get（Zone.class，new BigDecimal（request.getParameter（zoneId）））; 
 c.setZone（z）; 
 session.save（c）; 
 
 session.flush（）; 
 //session.refresh(c）; 
 System.out.println（c.getCountryId（））; //尝试显示序列值。 
 session.getTransaction（）。commit（）; 
  

这条语句 System.out.println（c.getCountryId（））;此代码中的尝试在插入完成后显示当前生成的序列值。

在Oracle表中的序列生成值被插入 2的倍数，即，就像414,416,418,420 ...将它们插入414,415,416,417,418,419,420 ...等链中。假设，当前在Oracle表中插入的序列值是 426 ，这个语句 System.out.println（c.getCountryId（））; 显示 425 （而在Oracle表的 COUNTRY_ID 列中，插入的值是 426

可能是由于某些原因，该序列执行了两次

。

---

在我的Hibernate POJO中，我指定了 countryId 主键列如下，

  @Id 
 @Column（名称= COUNTRY_ID）
 @SequenceGenerator（名称= CountryIdSequence，sequenceName =COUNTRY_SEQ ）
 @GeneratedValue（strategy = GenerationType.SEQUENCE，generator =Co untryIdSequence）
 private long countryId; 
  

在 Country.hbm.xml 映射中文件中，此列 countryId 映射如下。

 < id name =countryIdtype =long> 
< column name =COUNTRY_IDprecision =35scale =0/> 
< generator class =sequence> 
< param name =sequence> COUNTRY_SEQ< / param> 
< / generator> 
< / id> 
  

我在这里错过了什么？

解决方案

确实有一个针对 COUNTRY 表的触发器，该表由Oracle GUI工具自动创建，用于将序列与主键列关联 COUNTRY_ID 。

该序列由Hibernate执行两次，再由触发器执行。我暂时停用了触发器，该方法按预期工作。

I have the following code that attempts to fetch a generated sequence value for the primary key column COUNTRY_ID of the COUNTRY table in my Oracle (10g) database.

Country c=new Country();

c.setCountryName(request.getParameter("txtCountryName"));
c.setCountryCode(request.getParameter("txtCountryCode"));
Zone z=(Zone) session.get(Zone.class, new BigDecimal(request.getParameter("zoneId")));
c.setZone(z);
session.save(c);

session.flush();
//session.refresh(c);
System.out.println(c.getCountryId()); //Attempts to display the sequence value.
session.getTransaction().commit();     

This statement System.out.println(c.getCountryId()); in this codes attempts to display the currently generated sequence value after insertion is done.

Sequence generated values in the Oracle table are inserted in multiple of 2 i.e something like this 414, 416, 418, 420... instead of being inserted them in a chain like 414, 415, 416, 417, 418, 419, 420...

Suppose, the currently inserted sequence value in the Oracle table is 426, this statement System.out.println(c.getCountryId()); shows 425 (whereas in the COUNTRY_ID column in the Oracle table, the inserted value is 426).

Presumably, it appears that the sequence is executed twice for some reasons.

---

In my Hibernate POJO, I have designated the countryId primary key column as follows,

@Id
@Column(name = "COUNTRY_ID")
@SequenceGenerator(name = "CountryIdSequence", sequenceName = "COUNTRY_SEQ")
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "CountryIdSequence")
private long countryId;

In the Country.hbm.xml mapping file, this column countryId is mapped as follows.

<id name="countryId" type="long">
  <column name="COUNTRY_ID" precision="35" scale="0"/>
  <generator class="sequence">
    <param name="sequence">COUNTRY_SEQ</param>
  </generator>
</id>

What am I missing here?

解决方案

I indeed had a trigger against the COUNTRY table which is automatically created by an Oracle GUI tool to associate the sequence with the primary key column COUNTRY_ID.

The sequence was being executed twice once by Hibernate and again by the trigger. I disabled the trigger temporarily and the approach worked as intended.

这篇关于主键字段的Oracle序列不会检索Hibernate中当前插入的值的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！