Issue when retrieving result from Neo4JRepository

Drivers & Stacks
1

Hello, I'm having an issue with deserializing a simple query using a Neo4JRepository in an example I wrote.

PersonRepository has the following method signature:

public interface PersonRepository extends Neo4jRepository<Person, String> {
...
    @Query( "MATCH (p:Person{name: $pName})-[:LOCATED_IN]-(a:Address)" +
            "MATCH (p:Person)-[:HAS]-(w:Wealth)" +
            "MATCH (p:Person)-[s:STUDIED_IN]-(o:Organization)" +
            "RETURN p.id AS id, a AS address, w AS wealth, s AS education")
    Collection<PersonDetails> getPersonDetails(@Param("pName") String personName);

The PersonDetails result object looks like this:

@Value
public class PersonDetails {
    String id;
    Address address;
    Wealth wealth;
    Collection<StudiedIn> education;
}

Address and Wealth are entities also annotated as @Value.

StudiedIn Looks like this:

@Value
@RequiredArgsConstructor
@RelationshipProperties
public class StudiedIn {
    @Id
    @GeneratedValue
    private Long id;

    private final String degree;
    private final int year;

    @TargetNode
    private final Organization organization;
}

When I use the method, I get the following error:

2021-03-09 16:31:05.057 DEBUG 15888 --- [nio-8888-exec-3] org.springframework.data.neo4j.cypher    : Executing:
MATCH (p:Person{name : $pName})-[:LOCATED_IN]-(a:Address)MATCH (p:Person)-[:HAS]-(w:Wealth)MATCH (p:Person)-[s:STUDIED_IN]-(o:Organization)RETURN p.id AS id, a AS address, w AS wealth, s AS education
2021-03-09 16:31:05.085  WARN 15888 --- [nio-8888-exec-3] .r.s.Neo4jPersistenceExceptionTranslator : Don't know how to translate exception of type class org.springframework.data.neo4j.core.mapping.NoRootNodeMappingException
2021-03-09 16:31:05.086 DEBUG 15888 --- [nio-8888-exec-3] o.s.web.servlet.DispatcherServlet        : Failed to complete request: org.springframework.data.neo4j.core.mapping.NoRootNodeMappingException: Could not find mappable nodes or relationships inside Record<{id: "0220682345", address: node<165>, wealth: node<164>, education: relationship<292>}> for org.springframework.data.neo4j.core.mapping.DefaultNeo4jPersistentEntity@6c8d8b60

Do I explicitly need to map the result with the type? I understood that was implicit because of the Repository method signature definition. Surely I'm missing something else. Could you help me with this?

2

Hi team,

is there any solution for this issue as i have the same issue?

Thanks,

Radhakrishna.

3

Hi, I'm also running into the same problem.

Specifically, I have defined an interface-based projection to retrieve a view of a persisted entity from the database through a custom query. However, when I try to run the query from the backend, I get the following error:

org.springframework.data.neo4j.core.mapping.NoRootNodeMappingException: Could not find mappable nodes or relationships inside Record <{name: "Sara", age: 27, sex: "M", occupation: "Worker"}> for org.springframework.data.neo4j.core.mapping.DefaultNeo4jPersistentEntity@30aec673

Here is my custom query (inside a Neo4j Spring repository with root entity Student):

@Query("MATCH (students:Students)-[:LIKES]->()<-[:TEACHES]-(teacher: Teacher {email : $email}) "
+ "WHERE NOT (teacher)-->(students) "
+ "RETURN DISTINCT students.name, students.age, students.sex, students.occupation")
List<StudentCandidate> findUnmetLikingStudents(String email);

here is my StudentCandidate (the projection interface):

public interface StudentCandidate {

String getName();

int getAge();

String getSex();

String getOccupation();

}

and here's my Student class (with most details edited out for brevity's sake):

@Node
public class Student extends Person implements Positionable {

  @Id
  private String id;
  private double latitude;
  private double longitude;
  private int maxDistance;
  private Sex roommateSex;
  private int roommateAge;

  public Student(String username, String password, boolean enabled, boolean accountNonExpired,
      boolean credentialsNonExpired, boolean accountNonLocked, String email, String name, int age,
      String sex, String occupation, double latitude, double longitude, int maxDistance, String roommateSex, int roommateAge) {
    super(username, password, enabled, accountNonExpired, credentialsNonExpired, accountNonLocked,
        new HashSet<>(Arrays.asList(new UserAuthority(UserRole.STUDENT))), email, name, age, sex,
        occupation);
    id = UUID.randomUUID().toString();
    this.latitude = latitude;
    this.longitude = longitude;
    this.maxDistance = maxDistance;
    this.setRoommateSex(roommateSex);
    this.roommateAge = roommateAge;
  }

as you may see, some properties (including those in the interface projection) are actually set in the Person superclass. I don't know if that's relevant.

Is there something I'm doing wrong or is this functionality not actually supported?