@RelationshipEntity not hydrated [DATAGRAPH-961]

[spring-projects-issues]

Agostino Semeria opened DATAGRAPH-961 and commented

The same code, executed with the new snapshot version of spring-data-neo4j (4.2.0.BUILD-20170123.104601-200) doesn't return the existent relationship

@Query("MATCH (a:User) - [r:FRIEND_WITH] -> (b:Person) RETURN r, a, b")
FriendshipEntity loadFriendship(...);

@RelationshipEntity(type="FRIEND_WITH")
public class FriendshipEntity {
    @GraphId   private Long relationshipId;
    @StartNode private User user;
    @EndNode   private Person person;
}

The same code executed with the previous version (4.2.0.BUILD-20161223.121144-184) works well

---

Affects: 4.2 RC1 (Ingalls), 4.2 GA (Ingalls)

Reference URL: http://stackoverflow.com/questions/41824592/relationshipentity-not-hydrated

Attachments:

• screenshot-1.png (10.19 kB)

Backported to: 4.2.1 (Ingalls SR1)

1 votes, 3 watchers

[spring-projects-issues]

G'Kar commented

Hi there,

I might have encountered a related issue. I'm able to retrieve a RelationshipEntity with the following query:

@Query("match (p:PostNode) - [pr:POST_RECEPTION] -> (rn:ReceivedPostsNode) where p.postID={0} and pr.postRetrieved = FALSE and rn.userid = {1} return p, rn, pr")
public PostReceptionRel findBypostId(String postId, String userid);

My relationship entity is as follows:

@RelationshipEntity(type = "POST_RECEPTION")
public class PostReceptionRel
{
	@GraphId	Long id;
	private boolean postRetrieved = false;
	private boolean postRead = false;
	@StartNode	private PostNode postNode = null;
	@EndNode	private ReceivedPostsNode receivedPostsNode = null;
}

However if I update the relationship a phantom node is created which screws up a lot of subsequent procedures. Please see attached screenshot.

I'm using:
spring-data-neo4j:5.0.0.M1
neo4j-ogm-bolt-driver:2.1.0

[spring-projects-issues]

Agostino Semeria commented

According to this commit neo4j/neo4j-ogm@7712030
before this modification on method getRelationshipEntity() (https://github.com/neo4j/neo4j-ogm/blob/771203031c0f0ffbc528ac1a9cc1d1db5e8cc3d9/core/src/main/java/org/neo4j/ogm/context/GraphEntityMapper.java#L505) it was not needed to have e reference to the relationship entity in either the source or target node.

Which is the right behaviour?

[spring-projects-issues]

Nicolas Mervaillie commented

Can you detail your use case pls ?
Having to declare the relationships in your entities is problematic for you ?

[spring-projects-issues]

Agostino Semeria commented

Before the 4.2.0 this code worked well

@Query("MATCH (a:User) - [r:FRIEND_WITH] -> (b:Person) RETURN r, a, b")
FriendshipEntity loadFriendship(...);
 
@RelationshipEntity(type="FRIEND_WITH")
public class FriendshipEntity {
    @GraphId   private Long relationshipId;
    @StartNode private User user;
    @EndNode   private Person person;
}

@NodeEntity(label = "User")
public class User {
    @Property(name = "firstName")
    private String mFirstName;

    @Property(name = "lastName")
    private String mLastName;

    public String getFirstName() {
        return mFirstName;
    }

    public void setFirstName(String pFirstName) {
        mFirstName = pFirstName;
    }

    public String getLastName() {
        return mLastName;
    }

    public void setLastName(String pLastName) {
        mLastName = pLastName;
    }
}

@NodeEntity(label = "Person")
public class Person {
    @Property(name = "firstName")
    private String mFirstName;

    @Property(name = "lastName")
    private String mLastName;

    public String getFirstName() {
        return mFirstName;
    }

    public void setFirstName(String pFirstName) {
        mFirstName = pFirstName;
    }

    public String getLastName() {
        return mLastName;
    }

    public void setLastName(String pLastName) {
        mLastName = pLastName;
    }
}

After the 4.2.0 to make this code works I need to add this properties at least to User entity (source entity of the relationship)

@Relationship(type = "FRIEND_WITH")
 private FriendshipEntity mFriendship;

[spring-projects-issues]

Nicolas Mervaillie commented

Sorry I've been unclear.

I've seen that the behavior changed since 4.2.
What I try to understand is : what's the use case of not specifying the relations in your entities ?
To me, it is unusual to navigate only from relation to entity, and not the inverse.

Is it a strong requirement for you ?
Would adding the relationship be problematic for you ?

[spring-projects-issues]

Nicolas Mervaillie commented

fixed by neo4j/neo4j-ogm#309