Question

我有两个JPA实体：一个可以拥有多个AuthTokens的用户。用户没有引用其AuthTokens，而是AuthToken引用了其用户。看起来像这样：

@Entity
public class AuthenticationToken {
  @Id
  private String value;

  @ManyToOne
  private User user;

  ...
}

问题在于，有时我必须从数据库中删除所有用户，然后从某处重新导入并使用与以前相同的ID插入它们。并且，应该保留AuthTokens，并且他们的“用户”属性应该再次有效。但是，当我尝试删除用户时（在重新导入它们之前），我收到以下异常：

com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Cannot delete or update a parent row: a foreign key constraint fails

我正在使用MySQL数据库。问题是什么？我应该以其他方式解决问题吗？

更新这是我得到的例外：

    org.springframework.dao.DataIntegrityViolationException: could not execute statement; SQL [n/a]; constraint [null]; nested exception is org.hibernate.exception.ConstraintViolationException: could not execute statement
    at org.springframework.orm.jpa.vendor.HibernateJpaDialect.convertHibernateAccessException(HibernateJpaDialect.java:189)
    at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:155)
    at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:519)
    at org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:757)
    at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:726)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:478)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:272)
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:95)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:136)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodIntercceptor.invoke(CrudMethodMetadataPostProcessor.java:111)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:207)
    at com.sun.proxy.$Proxy67.deleteAll(Unknown Source)
    at hu.cargolink.backend.spreadsheets.SpreadsheetImportService.doJob(SpreadsheetImportService.java:62)
    at hu.cargolink.backend.utils.AsyncService$1.run(AsyncService.java:16)
    at java.lang.Thread.run(Thread.java:695)
Caused by: org.hibernate.exception.ConstraintViolationException: could not execute statement
    at org.hibernate.exception.internal.SQLExceptionTypeDelegate.convert(SQLExceptionTypeDelegate.java:72)
    at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:49)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:126)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:112)
    at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:190)
    at org.hibernate.engine.jdbc.batch.internal.NonBatchingBatch.addToBatch(NonBatchingBatch.java:62)
    at org.hibernate.persister.entity.AbstractEntityPersister.delete(AbstractEntityPersister.java:3400)
    at org.hibernate.persister.entity.AbstractEntityPersister.delete(AbstractEntityPersister.java:3630)
    at org.hibernate.action.internal.EntityDeleteAction.execute(EntityDeleteAction.java:114)
    at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:463)
    at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:349)
    at org.hibernate.event.internal.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:350)
    at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:56)
    at org.hibernate.internal.SessionImpl.flush(SessionImpl.java:1222)
    at org.hibernate.internal.SessionImpl.managedFlush(SessionImpl.java:425)
    at org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.beforeTransactionCommit(JdbcTransaction.java:101)
    at org.hibernate.engine.transaction.spi.AbstractTransactionImpl.commit(AbstractTransactionImpl.java:177)
    at org.hibernate.jpa.internal.TransactionImpl.commit(TransactionImpl.java:77)
    at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:515)
    ... 17 more
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Cannot delete or update a parent row: a foreign key constraint fails (`cargolink`.`authentication_token`, CONSTRAINT `FK_qtxnyq3pcsdqce9fiyw0hq6es` FOREIGN KEY (`sofor_id`) REFERENCES `sofor` (`id`))
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:408)
    at com.mysql.jdbc.Util.getInstance(Util.java:383)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1049)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4226)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4158)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2615)
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2776)
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2840)
    at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2082)
    at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2334)
    at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2262)
    at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2246)
    at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:187)
    ... 31 more

UPDATE2： 上面的堆栈跟踪中的我的用户实体实际上被称为“Sofor”，但我认为这并不重要。

UPDATE3： 我已经通过这种方式启用了表格的自动创建：

@Bean
    public JpaVendorAdapter jpaVendorAdapter() {
        HibernateJpaVendorAdapter hibernateJpaVendorAdapter = new HibernateJpaVendorAdapter();
        hibernateJpaVendorAdapter.setGenerateDdl(true);
        hibernateJpaVendorAdapter.setDatabase(Database.MYSQL);
        return hibernateJpaVendorAdapter;
    }

UPDATE4： 最终我不得不应用一个野蛮的解决方法：我正在存储被引用实体的id。 :-(但我仍然认为这不是一个真正的解决方案。

Answer 1

您可以像这样映射关联：

@ManyToOne(optional=true)
@JoinColumn(name="user_id", nullable=true)

如果这样做，请确保您的代码处理AuthenticationToken.getUser（）== null;

的情况

Answer 2

当我读到它时，你已经在你的桌子上了：

tokens

user
您从表user
它不起作用，因为存在外键违规

然后，您可以在导入脚本中忽略这些外键：http://gauravsohoni.wordpress.com/2009/03/09/mysql-disable-foreign-key-checks-or-constraints/

SET foreign_key_checks = 0;
DELETE FROM users where id > 45;
INSERT INTO ...
SET foreign_key_checks = 1;

您还可以使用Mysql工作台创建数据库转储，这也将禁用这些密钥。然后，您可以根据案例调整转储。

请注意，它与您的建模无关。

JPA @ManyToOne - 我不想要级联删除

2 个答案: