Relationship property not persisted in graph

Question

Context

• SDN 3.3.0.RELEASE / 3.4.0.M1
• Neo4j 2.1.7 in distant server mode.

Use case

I have an existing Person in database which can have multiple PersonTranslatedContent that can be in several languages. So basicaly, my modelisation is like :

(:Person)-[:TRANSLATION {lang:"fr}]->(:PersonTranslatedContent)

Problem

When I create a PersonTranslatedContent node and a TRANSLATION relation to link with my Person, the 'lang' property is not persisted on the relationship. The nodes are corecctly created, but when I query the database from the Neo4j browser, my relationship has only one property : _type__ : PersonToPersonTranslatedContent

Analysis

When logging the HTTP request received by Neo4j, the requets performed are in this order :

 1. MATCH (n) WHERE id(n) = {id_n}  MATCH (m) WHERE id(m) = {id_m}  CREATE (n)-[r:`TRANSLATION`]->(m) SET r={props}  RETURN id(r) as id, type(r) as type, r as properties, id(startNode(r)) as start, id(endNode(r)) as end
 2. START r=rel({id})  SET r.`_ _type_ _` = {value}
 3. START r=rel({id})  RETURN id(r) as id, type(r) as type, r as properties, id(startNode(r)) as start, id(endNode(r)) as end
 4. **START r=rel({id})  SET r.`lang` = {value}** <-- here the lang property seems to be correctly set !
 5. START r=rel({id})  SET r = {props} <- here, props = {"_ _type_ _" : PersonToPersonTranslatedContent"}

All those REST calls are done within a simple call to personToPersonTranslatedContentRepository.save(). I followed the white rabit in debug mode and here is the shortened call stack :

• Neo4jEntityConverterImpl.write() --> entityStateHandler.useOrCreateState() --> RestAPICypherImpl.createRelationship() (correspond to bullet 1)
• Neo4jEntityConverterImpl.write() --> typeMapper.writeType() --> RestAPICypherImpl.setPropertyOnEntity() (correspond to bullet 2)
• Neo4jEntityConverterImpl.write() --> sourceStateTransmitter.copyPropertiesTo() --> persistentEntity.doWithProperties() --> RestAPICypherImpl.setPropertyOnEntity() (correspond to bullet 4)
• Neo4jEntityConverterImpl.write() --> sourceStateTransmitter.copyPropertiesTo() --> ((UpdateableState)target).flush() --> RestAPICypherImpl.setPropertiesOnEntity() (correspond to bullet 5)

So, in my opinion considering what I know and what I saw during debug, the problem seems to be around the "propertyData" attribute of class RestEntity which is used in the ((UpdateableState)target).flush() ! It always hold the value {"_ type _" : PersonToPersonTranslatedContent"} but never contains my "lang" property.

Note : my problem is the same as the one explain here 3.3.0.M1 : Properties on RelationShipEntity not saved when using CypherRestGraphDatabase?. His post has no satisfying answer.

Can you help me (and him I guess) ?

Thx :)

13/07/15 : Updated

I finally manage to resolve my problem by using :

Map<String, Object> properties = new HashMap<>(); properties.put("lang", lang); properties.put("__type__", "UserToUserTranslatedContent");
neo4jOperations.createRelationshipBetween(neo4jOperations.getNode(user.getId()), neo4jOperations.getNode(translatedContent.getId()), RelationNames.TRANSLATION, properties);

But it is still strange that simple save() operation do not work as expected

Answer 1

For people looking for a fix, I made a report concerning this problem (https://jira.spring.io/browse/DATAGRAPH-699) and a quick way to use SDN like before (< 3.3.x) is doing like this:

remove "spring-data-neo4j" and "spring-data-neo4j-rest" from your build.gradle and add these lines:

repositories {
        maven {
            url "https://jitpack.io"
        }
    }

dependencies {
    compile 'org.springframework:spring-orm:4.1.7.RELEASE'
    compile 'org.springframework:spring-aspects:4.1.7.RELEASE'
    compile 'com.github.nousmotards:spring-data-neo4j:3.3.1.NM1'
}

Hope this will help in the mean time of having a real fix ;)