Does or will Spring Data Neo4j 4.0 support @Query annotations in node entities ?
Leward
With Spring Data Neo4j 3.X I used to have the following in my entities:
@NodeEntity
public class Agency {
@GraphId
private Long id;
private String name
@Query("start n=node({self}) match n<-[:BELONG_TO]-(u:User) return count(u);")
private int numberOfEmployees;
}However in SDN 4.0.0M1 the @Query annotation only applies to method. It is written in the documentation that this works for repository methods, however nothing is mentioned about using the @Query annotation.
Does SDN support such a thing?
If the answer is no, I guess I can make it work in one query with Cypher (getting the agency and the count of agency members), but then how to map it back to a proper SDN entity?
Kind Regards,
Leward
Sumit Gupta
Leward
If you look at the source code for @Query here: https://github.com/spring-projects/spring-data-neo4j/blob/4.0/spring-data-neo4j/src/main/java/org/springframework/data/neo4j/annotation/Query.java you will see the following:
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
@QueryAnnotation
@Documented
public @interface Query {It states that the annotation will work only when applied to methods.
Luanne Coutinho
Hi
@Query is currently only available on Repository methods. We discussed adding it to domain entity classes, and decided to defer that for M1, primarily for complexity/performance reasons. (Imagine a node entity with 10 @Query annotations and then a request to load a couple of hundred of those entities in one go). In the worst case (naive) scenario, a single request end up hitting the database thousands of times.
As an alternative, you can do this:
```
public class Agency {
@Relationship(type="BELONG_TO", direction=Relationship.INCOMING)
private List<Employee> employees
private int numberOfEmployees() {
return employees.size();
}
}
```
By default, when you load an entity, its immediate neighbours in the graph will be loaded as well, so you get the Employees information when you make a request for an Agency.
On behalf of Vince Bickers.
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