使用Scala在Neo4j中索引关系

Question

假设两个节点之间存在如下关系

start --> "follows" --> end

我想创建一个名为"Relations"的索引，并将上面的关系添加到索引中。如何在Scala或Java中实现呢?

我试过这样做:

override def NodeIndexConfig = ("Relations", Some(Map("provider" -> "lucene", "type" -> "fulltext")))::NIL
    val rel_name = group+"_Voteup"
    val relation = user_node --> rel_name --> item_node
    val Relation_Index = getNodeIndex("Relations").get
    val rel_value = user_id+item_id+rel_name
    Relation_Index += (relation,"rel_id",rel_value)

但是，我得到类型不匹配错误。

Answer 1

您可能应该使用关系索引而不是节点索引，如

override def RelationIndexConfig = ("Relations", Some(Map("provider" -> "lucene", "type" -> "fulltext")))::Nil
val rel_name = group+"_Voteup"
val relation = user_node --> rel_name --> item_node
val Relation_Index = getRelationIndex("Relations")
val rel_value = user_id+item_id+rel_name
Relation_Index.foreach(_ += (relation,"rel_id",rel_value))

注意:我删除了index.get调用，并对可选值使用了"更安全"的foreach调用。