爲什麼Neo4j創建節點[0]？

Question

我想使用的Neo4j的Java API下面簡單的例子：

public void createDB(String datasetRoot) { 
GraphDatabaseService graphDb = new GraphDatabaseFactory().newEmbeddedDatabase("data/Neo4jTest1"); 
registerShutdownHook(graphDb); 

Transaction tx = graphDb.beginTx(); 
try { 
    // Database operations go here 
    Node firstNode = graphDb.createNode(); 
    firstNode.setProperty("nodeId", "1"); 
    Node secondNode = graphDb.createNode(); 
    secondNode.setProperty("nodeId", "2"); 

    Relationship relationship = firstNode.createRelationshipTo(secondNode, RelTypes.SIMILAR); 

    tx.success(); 
} 
finally { 
    tx.finish(); 
} 

當我試圖打印所有創建的節點，我注意到了一個節點，沒有財產產生了[0]。這是爲什麼發生？

Answer 1

這在Neo4j中被稱爲參考節點。這是neo4j的默認行爲。它將創建一個節點id爲0且沒有屬性的節點。

請檢查該https://github.com/neo4j/neo4j/issues/175