Spring数据映射无法按预期工作

Question

I have a table option with two foreign keys and many-to-one associations (to tables checkpoint and setting ): db schema .

From JPA side I have 2 bidirectional associations: with Cascade.ALL and FetchType.EAGER on the one side and Cascade.REMOVE on the second side. Here is corresponding JPA mappings:

@Entity
@Table(name = "checkpoint")
@AllArgsConstructor
@NoArgsConstructor
@Data
public class Checkpoint {

  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  private long id;

  private long location;

  @OneToMany(mappedBy = "checkpoint",
        cascade = CascadeType.ALL,
        orphanRemoval = true,
        fetch = FetchType.EAGER)
  private List<RewardOption> rewardOptions = new ArrayList<>();
}

@Entity
@Table(name = "setting")
@AllArgsConstructor
@NoArgsConstructor
@Data
public class RewardSetting {

  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  private long id;

  @Column(name = "base_line")
  private long baseLine;

  @OneToMany(mappedBy = "rewardSetting",
        cascade = CascadeType.REMOVE,
        orphanRemoval = true)
  private List<RewardOption> rewardOptions = new ArrayList<>();
}

@Entity
@Table(name = "option")
@AllArgsConstructor
@NoArgsConstructor
@Data
public class RewardOption {

  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  private long id;

  private long weight;

  @ManyToOne
  @JoinColumn(name = "setting_id")
  private RewardSetting rewardSetting;

  @ManyToOne
  @JoinColumn(name = "checkpoint_id")
  private Checkpoint checkpoint;
} 

Also I'm using Spring Data for entity manipulations. To me it seemed as working example, but on practice when I perform:

...
rewardSettingRepository.delete(rewardSetting);

Or:

...
rewardSettingRepository.delete(id);

I got JPA tries to remove a row from setting table BEFORE corresponding rows from a option table.

Does anyone have some ideas why it behaves this way? Why this mapping leads to this behaviour? How to do this right way?

The full stack trace is:

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:278) at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:244) at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:521) at org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:765) at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:734) at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:518) at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:292) at org.springframework.transac tion.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96) 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$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:133) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) at org.springframework.data.repository.core.support.Surrou ndingTransactionDetectorMethodInterceptor.invoke(SurroundingTransactionDetectorMethodInterceptor.java:57) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213) at com.sun.proxy.$Proxy82.delete(Unknown Source) at com.github.star67.hibernatefetchcascade.HibernateFetchCascadeApplication.testSettingDelete(HibernateFetchCascadeApplication.java:41) at com.github.star67.hibernatefetchcascade.HibernateFetchCascadeApplication.main(HibernateFetchCascadeApplication.java:36)

Caused by: org.hibernate.exception.ConstraintViolationException: could not execute statement at org.hibernate.exception.internal.SQLExceptionTypeDelegate.convert(SQLExceptionTypeDelegate.java:59) at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:42) at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:109) at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:95) at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:207) at org.hibernate.engine.jdbc.batch.internal.NonBatchingBatch.addToBatch(NonBatchingBatch.java:45) at org.hibernate.persister.entity.AbstractEntityPersister.delete(AbstractEntityPersister.java:3261) at org.hibernate.persister.entity.AbstractEntityPersister.delete(AbstractEntityPersister.java:3498) at org.hibernate.action.internal.EntityDeleteAction.execute(EntityDeleteAction.java:98) at org.hibernate.engine.sp i.ActionQueue.executeActions(ActionQueue.java:582) at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:456) at org.hibernate.event.internal.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:337) at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:39) at org.hibernate.internal.SessionImpl.flush(SessionImpl.java:1282) at org.hibernate.internal.SessionImpl.managedFlush(SessionImpl.java:465) at org.hibernate.internal.SessionImpl.flushBeforeTransactionCompletion(SessionImpl.java:2963) at org.hibernate.internal.SessionImpl.beforeTransactionCompletion(SessionImpl.java:2339) at org.hibernate.engine.jdbc.internal.JdbcCoordinatorImpl.beforeTransactionCompletion(JdbcCoordinatorImpl.java:485) at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl.beforeCompletionCallback(JdbcResourceLocalTransactionCoordinatorImpl.java:147) at org.hibernate.resource.tra nsaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl.access$100(JdbcResourceLocalTransactionCoordinatorImpl.java:38) at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl$TransactionDriverControlImpl.commit(JdbcResourceLocalTransactionCoordinatorImpl.java:231) at org.hibernate.engine.transaction.internal.TransactionImpl.commit(TransactionImpl.java:65) at org.hibernate.jpa.internal.TransactionImpl.commit(TransactionImpl.java:61) at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:517) ... 18 more

Caused by: java.sql.SQLIntegrityConstraintViolationException: Cannot delete or update a parent row: a foreign key constraint fails ( demo . option , CONSTRAINT FKdhs5wopt13o6b9gl4wydr0l9o FOREIGN KEY ( setting_id ) REFERENCES setting ( id )) at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:115) at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:95) at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122) at com.mysql.cj.jdbc.ClientPreparedStatement.executeInternal(ClientPreparedStatement.java:960) at com.mysql.cj.jdbc.ClientPreparedStatement.executeUpdateInternal(ClientPreparedStatement.java:1116) at com.mysql.cj.jdbc.ClientPreparedStatement.executeUpdateInternal(ClientPreparedStatement.java:1066) at com.mysql.cj.jdbc.ClientPreparedStatement.executeLargeUpdate(ClientPreparedStatement.java:1396) at com.mysql.cj.jdbc.ClientPreparedStatement.executeUpdate(ClientPreparedStatement.java:1051) at sun .reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.apache.tomcat.jdbc.pool.StatementFacade$StatementProxy.invoke(StatementFacade.java:114) at com.sun.proxy.$Proxy89.executeUpdate(Unknown Source) at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:204) ... 37 more

Also, after playing around I found some strange things, that I cannot explain:

1. Adding @ManyToOne(fetch = FetchType.LAZY) for Checkpoint in the class RewardOption fixes the problem, but how fetch type influences cascade?
2. Changing cascade = CascadeType.ALL to cascade = CascadeType.REMOVE in the class Checkpoint fixes the problem but I need ability to save cascade...

If anyone could throw some light on these "fixes" it would be great.

Here is the code to play around

Answer 1

To make it work, you need to synchronize both end of the bidirectional association .

That means, prior to calling delete, you need to make sure you disassociate the parent from al child entities.