Neo4j - 无法创建关系实体

Question

I am trying to insert the relationships between two nodes in Neo4j. I am using the Neo4J(2.1.8 Community) & spring-data-neo4j(3.3.0.RELEASE).

I am using trying to create the Employee-Manager relationship. This relationship entity is Report. (Both class are given below)

But when I am trying to save the relation ship

Employee manager = new Employee("Dev_manager", "Management");
Employee developer = new Employee("Developer", "Development");
developer.setReportsTo(manager);
developer.relatedTo(manager, "REPORTS_TO")
employeeRepository.save(developer);

I am getting exception as

Exception in thread "main" org.springframework.dao.DataRetrievalFailureException: RELATIONSHIP[0] has no property with propertyKey=" type ".; nested exception is org.neo4j.graphdb.NotFoundException: RELATIONSHIP[0] has no property with propertyKey=" type ".

Can any one please help me that what is exactly wrong in this code.

The same code works after I change the type of relations in Employee as

@RelatedToVia(type = "REPORT_TO", elementClass = Report.class, direction = Direction.INCOMING)

Note: I am using this reference for this tutorial.

Employee.java class

@NodeEntity
public class Employee {

@GraphId
private Long id;
private String name;
private String department;

@Fetch
@RelatedTo(type = "REPORTS_TO")
private Employee reportsTo; //Employee reports to some employee (i.e. Manager).

@Fetch
@RelatedTo(type = "REPORTS_TO", direction = Direction.INCOMING)
Set<Employee> directReport; //All the employees who reports to this particular this employee.

@Fetch
@RelatedToVia(type = "REPORTS_TO", elementClass = Report.class, direction = Direction.INCOMING)
Set<Report> relations = new HashSet<Report>(); // All the incoming relationship entities.
//*** Constructor, Getter-setters and other methods...
}

Report.java class

@RelationshipEntity(type = "REPORTS_TO")
public class Report {

@GraphId
private Long id;
private String title;

@Fetch
@StartNode
private Employee child;

@Fetch
@EndNode
private Employee parent;
//*** Constructor, Getter-setters and other methods...
}

**Update: ** I have created 2 relations using this class structure. And I got the below result.

It looks like it creates 2 relations between the node. 1 is empty relation using reportsTo(ie REPORTS_TO) and another relation using the relations(ie REPORT_TO). Can anyone please update why this is happening?

Answer 1

What's the different between: relations and directReport ?

I think SDN is just confused with all the duplicate listing of relationships?

Esp. if they are once declared as light relationships without type and once as relationship-entities.

I think for this case it is much clearer and easier to use

template.createRelationshipBetween(employee, manager, "REPORTS_TO");

Or just create, populate and save the relationship-entity Report .

Otherwise you have to make sure that all collections on all sides are consistent with each other.