使用hibernate删除多对一

时间：2013-06-01 06:01:35

标签： hibernate

鉴于具有下面列出的单个地址的Person的单向1-1映射示例，从一个人删除地址并删除数据库记录的正确方法是什么？将shipAddr字段设置为null会产生NPE。

// pseudo code that results in NPE
ses.beginTransaction();
person.setShipAddr(null);
dao.makePersistent(person);    
ses.getTransaction().commit();

解决方案：修改了基于Hibernate文档的伪代码，单值一对一或多对一关联不支持孤立删除。

 // correct pseudo code 
ses.beginTransaction();
addressDao.makeTransient(person.getShipAddr());    // explicitly delete address
person.setShipAddr(null);
dao.makePersistent(person);    
ses.getTransaction().commit();

班级定义：

class Person {
  private Long id;
  private Integer version;
  private Address shipAddr;
  // other fields
}

class Address {
  private Long id;
  private Integer version;
  // other fields
}

映射文件：

<class name="Person" >
    <id name="id" type="java.lang.Long">
        <column name="ID" />
        <generator class="native" />
    </id>
<version generated="never" name="version" type="java.lang.Integer" />
    <many-to-one name="shipAddr" class="Address" cascade="all-delete-orphan" unique="true" not-null="true" >
        <column name="SHIP_ADDRESS_ID" />
    </many-to-one>
</class>

<Class name="Address" >
    <id name="id" type="java.lang.Long">
        <column name="ID" />
        <generator class="native" />
    </id>
    <version generated="never" name="version" type="java.lang.Integer" />
</class>

将地址设置为空后保存时出现异常

java.lang.NullPointerException
at org.hibernate.engine.EntityEntry.getLoadedValue(EntityEntry.java:255)
at org.hibernate.engine.Cascade.cascadeProperty(Cascade.java:232)
at org.hibernate.engine.Cascade.cascade(Cascade.java:161)
at org.hibernate.engine.Cascade.cascade(Cascade.java:127)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.cascadeOnUpdate(DefaultSaveOrUpdateEventListener.java:376)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.performUpdate(DefaultSaveOrUpdateEventListener.java:350)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsDetached(DefaultSaveOrUpdateEventListener.java:246)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.performSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:112)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:93)
at org.hibernate.impl.SessionImpl.fireSaveOrUpdate(SessionImpl.java:685)
at org.hibernate.impl.SessionImpl.saveOrUpdate(SessionImpl.java:677)
at org.hibernate.impl.SessionImpl.saveOrUpdate(SessionImpl.java:673)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.hibernate.context.ThreadLocalSessionContext$TransactionProtectionWrapper.invoke(ThreadLocalSessionContext.java:345)
at com.sun.proxy.$Proxy7.saveOrUpdate(Unknown Source)
at com.easa.motordb.dao.internal.GenericHibernateDAO.makePersistent(GenericHibernateDAO.java:93)
at com.easa.motordb.services.internal.AbstractEntity.save(AbstractEntity.java:103)
at com.easa.motordb.services.test.IPersonEntityTest.removeAddress(IPersonEntityTest.java:62)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
at org.junit.runners.BlockJUnit4ClassRunner.runNotIgnored(BlockJUnit4ClassRunner.java:79)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:71)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:49)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
at org.eclipse.pde.internal.junit.runtime.RemotePluginTestRunner.main(RemotePluginTestRunner.java:62)
at org.eclipse.pde.internal.junit.runtime.CoreTestApplication.run(CoreTestApplication.java:23)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.eclipse.equinox.internal.app.EclipseAppContainer.callMethodWithException(EclipseAppContainer.java:587)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:198)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:344)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:622)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:577)
at org.eclipse.equinox.launcher.Main.run(Main.java:1410)
at org.eclipse.equinox.launcher.Main.main(Main.java:1386)

1 个答案:

答案 0 :(得分：2)

删除cascade="all-delete-orphan"。当你有一个子实体的集合时应该使用它，你想要在删除父实体时将其删除，因此孤立，所以我认为many-to-one关联不支持它。我建议你手动删除地址。

编辑：官方文档说：请注意，单值多对一关联不支持 5.1.7下的孤立删除。。映射一对一和一对多关联

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