JPA刪除一個多到一的關係

-1

@Entity 
public class Tag { 

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

    @OneToMany(cascade = CascadeType.ALL, orphanRemoval = true, mappedBy = "parent") 
    private List<TagValue> values; 

    private String name; 
} 

@Entity 
public class TagValue { 

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

    private String name; 

    @ManyToOne 
    private Tag parent; 
}

這兩個都是在父子關係和孩子知道它的父。當我嘗試刪除父母並且孩子仍在引用它時，我的問題就開始了。 Eclipse Link告訴我，我違反了外鍵約束，因爲一個孩子（TagValue）仍在引用它。如果孩子仍然有一個引用它，我該如何改變我目前的方法來刪除父母？

最後，我怎麼能告訴JPA刪除父母時引用父母的所有孩子？它必須像這樣工作。我知道父母知道這是使用列表的孩子會更容易，但那不是我所追求的。我玩過級聯和whatnot，但我似乎並沒有得到它。

編輯：

所以我被告知，它應該已經與我的代碼工作。由於它沒有，這裏是用例失敗和錯誤的堆棧跟蹤。

TagValue value = new TagValue(); 
value.setName("Testvalue"); 

Tag tag = new Tag(); 
tag.setName("Testtag"); 
value.setParent(tag); 
Database.addTag(tag); 
Database.addTagValue(value); 
Database.removeTag(tag);

數據庫類的方法被定義如下：

public static void addTag(final Tag tag) throws Exception { 
    manager.getTransaction().begin(); 
    manager.persist(tag); 
    manager.getTransaction().commit(); 
} 

public static void addTagValue(final TagValue value) throws Exception { 
    manager.getTransaction().begin(); 
    manager.persist(value); 
    manager.getTransaction().commit(); 
} 

public static void removeTag(final Tag tag) throws Exception { 
    manager.getTransaction().begin(); 
    manager.remove(tag); 
    manager.getTransaction().commit(); 
}

的堆棧跟蹤：

注：Auf Schlüssel (id)=(1) wird noch aus Tabelle „tagvalue「意味着密鑰(id)=(1)在表tagvalues仍然被引用。

[EL Warning]: 2015-02-24 11:12:43.785--UnitOfWork(390138887)--Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.5.2.v20140319-9ad6abd): org.eclipse.persistence.exceptions.DatabaseException 
Internal Exception: org.postgresql.util.PSQLException: FEHLER: Aktualisieren oder Löschen in Tabelle „tag「 verletzt Fremdschlüssel-Constraint „fk_tagvalue_parent_id「 von Tabelle „tagvalue「 
    Detail: Auf Schlüssel (id)=(1) wird noch aus Tabelle „tagvalue「 verwiesen. 
Error Code: 0 
Call: DELETE FROM TAG WHERE (ID = ?) 
    bind => [1 parameter bound] 
Query: DeleteObjectQuery(Tag(id=1, values=[], name=Testtag)) 
javax.persistence.RollbackException: Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.5.2.v20140319-9ad6abd): org.eclipse.persistence.exceptions.DatabaseException 
Internal Exception: org.postgresql.util.PSQLException: FEHLER: Aktualisieren oder Löschen in Tabelle „tag「 verletzt Fremdschlüssel-Constraint „fk_tagvalue_parent_id「 von Tabelle „tagvalue「 
    Detail: Auf Schlüssel (id)=(1) wird noch aus Tabelle „tagvalue「 verwiesen. 
Error Code: 0 
Call: DELETE FROM TAG WHERE (ID = ?) 
    bind => [1 parameter bound] 
Query: DeleteObjectQuery(Tag(id=1, values=[], name=Testtag)) 
    at org.eclipse.persistence.internal.jpa.transaction.EntityTransactionImpl.commit(EntityTransactionImpl.java:157) 
    at de.yabue.baka.YabueCentral.Persistence.Database.removeTag(Database.java:256) 
    at de.yabue.baka.YabueCentral.Persistence.DatabaseTest.testPersistence(DatabaseTest.java:50) 
    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:483) 
    at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:74) 
    at org.testng.internal.Invoker.invokeMethod(Invoker.java:673) 
    at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:846) 
    at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:1170) 
    at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:125) 
    at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:109) 
    at org.testng.TestRunner.runWorkers(TestRunner.java:1147) 
    at org.testng.TestRunner.privateRun(TestRunner.java:749) 
    at org.testng.TestRunner.run(TestRunner.java:600) 
    at org.testng.SuiteRunner.runTest(SuiteRunner.java:317) 
    at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:312) 
    at org.testng.SuiteRunner.privateRun(SuiteRunner.java:274) 
    at org.testng.SuiteRunner.run(SuiteRunner.java:223) 
    at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:52) 
    at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:86) 
    at org.testng.TestNG.runSuitesSequentially(TestNG.java:1039) 
    at org.testng.TestNG.runSuitesLocally(TestNG.java:964) 
    at org.testng.TestNG.run(TestNG.java:900) 
    at org.testng.remote.RemoteTestNG.run(RemoteTestNG.java:110) 
    at org.testng.remote.RemoteTestNG.initAndRun(RemoteTestNG.java:205) 
    at org.testng.remote.RemoteTestNG.main(RemoteTestNG.java:174) 
    at org.testng.RemoteTestNGStarter.main(RemoteTestNGStarter.java:125) 
    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:483) 
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:134) 
Caused by: Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.5.2.v20140319-9ad6abd): org.eclipse.persistence.exceptions.DatabaseException 
Internal Exception: org.postgresql.util.PSQLException: FEHLER: Aktualisieren oder Löschen in Tabelle „tag「 verletzt Fremdschlüssel-Constraint „fk_tagvalue_parent_id「 von Tabelle „tagvalue「 
    Detail: Auf Schlüssel (id)=(1) wird noch aus Tabelle „tagvalue「 verwiesen. 
Error Code: 0 
Call: DELETE FROM TAG WHERE (ID = ?) 
    bind => [1 parameter bound] 
Query: DeleteObjectQuery(Tag(id=1, values=[], name=Testtag)) 
    at org.eclipse.persistence.exceptions.DatabaseException.sqlException(DatabaseException.java:340) 
    at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.processExceptionForCommError(DatabaseAccessor.java:1611) 
    at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeDirectNoSelect(DatabaseAccessor.java:898) 
    at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeNoSelect(DatabaseAccessor.java:962) 
    at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.basicExecuteCall(DatabaseAccessor.java:631) 
    at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeCall(DatabaseAccessor.java:558) 
    at org.eclipse.persistence.internal.sessions.AbstractSession.basicExecuteCall(AbstractSession.java:2002) 
    at org.eclipse.persistence.sessions.server.ClientSession.executeCall(ClientSession.java:298) 
    at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeCall(DatasourceCallQueryMechanism.java:242) 
    at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeCall(DatasourceCallQueryMechanism.java:228) 
    at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.deleteObject(DatasourceCallQueryMechanism.java:210) 
    at org.eclipse.persistence.internal.queries.StatementQueryMechanism.deleteObject(StatementQueryMechanism.java:104) 
    at org.eclipse.persistence.queries.DeleteObjectQuery.executeDatabaseQuery(DeleteObjectQuery.java:218) 
    at org.eclipse.persistence.queries.DatabaseQuery.execute(DatabaseQuery.java:899) 
    at org.eclipse.persistence.queries.DatabaseQuery.executeInUnitOfWork(DatabaseQuery.java:798) 
    at org.eclipse.persistence.queries.ObjectLevelModifyQuery.executeInUnitOfWorkObjectLevelModifyQuery(ObjectLevelModifyQuery.java:108) 
    at org.eclipse.persistence.queries.DeleteObjectQuery.executeInUnitOfWorkObjectLevelModifyQuery(DeleteObjectQuery.java:119) 
    at org.eclipse.persistence.queries.ObjectLevelModifyQuery.executeInUnitOfWork(ObjectLevelModifyQuery.java:85) 
    at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.internalExecuteQuery(UnitOfWorkImpl.java:2896) 
    at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1804) 
    at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1786) 
    at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1737) 
    at org.eclipse.persistence.internal.sessions.CommitManager.deleteAllObjects(CommitManager.java:336) 
    at org.eclipse.persistence.internal.sessions.CommitManager.deleteAllObjects(CommitManager.java:285) 
    at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.commitToDatabase(UnitOfWorkImpl.java:1444) 
    at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.commitToDatabaseWithChangeSet(UnitOfWorkImpl.java:1531) 
    at org.eclipse.persistence.internal.sessions.RepeatableWriteUnitOfWork.commitRootUnitOfWork(RepeatableWriteUnitOfWork.java:277) 
    at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.commitAndResume(UnitOfWorkImpl.java:1169) 
    at org.eclipse.persistence.internal.jpa.transaction.EntityTransactionImpl.commit(EntityTransactionImpl.java:132) 
    ... 33 more 
Caused by: org.postgresql.util.PSQLException: FEHLER: Aktualisieren oder Löschen in Tabelle „tag「 verletzt Fremdschlüssel-Constraint „fk_tagvalue_parent_id「 von Tabelle „tagvalue「 
    Detail: Auf Schlüssel (id)=(1) wird noch aus Tabelle „tagvalue「 verwiesen. 
    at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2103) 
    at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1836) 
    at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:257) 
    at org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:512) 
    at org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2Statement.java:388) 
    at org.postgresql.jdbc2.AbstractJdbc2Statement.executeUpdate(AbstractJdbc2Statement.java:334) 
    at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeDirectNoSelect(DatabaseAccessor.java:890) 
    ... 59 more

我也試圖讓我想從數據庫中刪除第一之前，我刪除了標籤，但返回的實例已在values列表中沒有的項目。所以我最後的猜測是，我必須自己填寫values列表？

來源

2015-02-23 Ya Bü

您已經在使用cascade = ALL進行此操作。刪除父項應自動刪除子項。如果沒有，請顯示您的代碼和異常的堆棧跟蹤。 – 2015-02-23 20:27:55

作爲評論上面它應該已經工作（如果你打電話EM.remove不做批量刪除）。您可以在刪除之前添加Tag.values.clear（）。 – Zielu 2015-02-23 23:20:58

@JBNizet我添加了您請求的信息。我相信這是一個非常微不足道的錯誤，但我對JPA非常陌生，並且仍在努力尋找解決方法。 – 2015-02-24 10:36:47

就像我上次想到的那樣，我不得不親自填寫父母的名單。所以現在沒有更多的錯誤。

我改變了這種方法：

public static void addTagValue(final TagValue value) throws Exception { 
    manager.getTransaction().begin(); 
    manager.persist(value); 
    manager.getTransaction().commit(); 
}

到：

public static void addTagValue(final TagValue value) throws Exception { 
    manager.getTransaction().begin(); 
    value.getParent().getValues().add(value); 
    manager.persist(value); 
    manager.getTransaction().commit(); 
}

這裏是我爲什麼不考慮在此之前：首先，我總覺得，那mappedBy自動會做這項工作。此外，我使用lombok來生成我的setter和getters，並通過@Data註釋完成。此註釋生成所有設置者和獲取者，但也包括toString()和hashCode()方法。當我向values列表中添加項目時，hashCode()方法產生了一個Stackoverflow，我必須先解決這個問題。

來源

2015-02-24 10:52:24

JPA刪除一個多到一的關係

回答

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