ConstraintViolationException當使用UniqueNodeFactory創建節點

此測試失敗，錯誤，我不明白爲什麼.. 我認爲UniqueNodeFactory只有當它不存在時創建節點。當然，我可以使用Cypher做同樣的事情，但我想了解這裏會發生什麼.. 有人可以解釋嗎？我正在使用neo4j 2.3.1。ConstraintViolationException當使用UniqueNodeFactory創建節點

public class SimpleTest { 

private GraphDatabaseService graphService; 

@Before 
public void setUp() throws Exception { 
    graphService = new TestGraphDatabaseFactory().newImpermanentDatabase(); 
    graphService.execute("CREATE CONSTRAINT ON (user:User) ASSERT user.userId IS UNIQUE"); 
} 

@After 
public void tearDown() throws Exception { 
    graphService.shutdown(); 
} 

public static UniqueFactory.UniqueNodeFactory createUserFactory(GraphDatabaseService graphDatabaseService) { 

    return new UniqueFactory.UniqueNodeFactory(graphDatabaseService, "User") { 

     @Override 
     protected void initialize(Node created, Map<String, Object> properties) { 
      created.addLabel(DynamicLabel.label("User")); 
      created.setProperty("userId", properties.get("userId")); 
     } 
    }; 
} 

@Test 
public void testCreateUser() throws Exception { 
    try (Transaction tx = graphService.beginTx()) { 
     Node node = graphService.createNode(DynamicLabel.label("User")); 
     node.setProperty("userId", 100L); 
     tx.success(); 
    } 

    try (Transaction tx = graphService.beginTx()) { 
     UniqueFactory.UniqueNodeFactory uniqueFactory = createUserFactory(graphService); 
     uniqueFactory.getOrCreate("userId", 100L); 
     tx.success(); 
    } 
} 

}

錯誤：

Caused by: org.neo4j.kernel.api.exceptions.schema.UniquePropertyConstraintViolationKernelException: Node 0 already exists with label 0 and property 0=100 
at org.neo4j.kernel.impl.api.ConstraintEnforcingEntityOperations.validateNoExistingNodeWithLabelAndProperty(ConstraintEnforcingEntityOperations.java:165) 
at org.neo4j.kernel.impl.api.ConstraintEnforcingEntityOperations.nodeSetProperty(ConstraintEnforcingEntityOperations.java:140) 
at org.neo4j.kernel.impl.api.LockingStatementOperations.nodeSetProperty(LockingStatementOperations.java:453) 
at org.neo4j.kernel.impl.api.OperationsFacade.nodeSetProperty(OperationsFacade.java:896) 
at org.neo4j.kernel.impl.core.NodeProxy.setProperty(NodeProxy.java:293) 
... 33 more

來源

2016-03-02 Mike

好了，現在我看到的原因。我創建了模式索引與Cypher和UniqueNodeFactory使用傳統索引。要解決此問題，只需使用UniqueNodeFactory即可創建節點。

來源

2016-03-03 13:26:07 Mike

ConstraintViolationException當使用UniqueNodeFactory創建節點

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