Indexing relationships in Neo4j using Scala

Question

Say that there is a relationship between 2 nodes as below

start --> "follows" --> end

I want to create an index named "Relations" and add the above relation to the index. How do I do that in Scala or in Java?

I tried doing it this way :

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)

But, am getting Type mismatch error.

Answer 1

You should probably use the relation index instead of the node index, like

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))

NOTE: I removed the index.get call and used a "safer" foreach call on the optional value.