How to fetch pattern variable with node and relationships (if present)

Suppose, we have the following data in neo4j DB ->

The java entity representation is as follows ->

@NodeEntity
public class Place
@Id
@GeneratedValue
private Long id;

private String name;


@NodeEntity
public class Monument
@Id
@GeneratedValue
private Long id;

private String name;


@NodeEntity
public class Person
@Id
@GeneratedValue
private Long id;

private String name;

@Relationship(type = "VISITED", direction = Relationship.OUTGOING)
private Monument monument;

@Relationship(type = "STAYS", direction = Relationship.OUTGOING)
private Place place;



Now, I want to fetch all persons also populating the linked place and monument, if present. This means, the cypher query will not only provide me List< Person> as result and the Monument and Place object should also be linked with each Person object, if the links are available (and otherwise null).
To clarify it further, for Person 'Ron', I should be able to see the monument he visited and the place he stays, without performing any more queries to fetch the relationships. Similarly, for Person 'April', I should be able to see where she stays, but will not know which monument she visited because there is no link there.

With my basic knowledge in Cypher Query language, I have tried but could not get the desired result.

MATCH
p=(place:Place)<-[STAYS]-(person:Person)-[VISITED]->(monument:Monument) RETURN p

MATCH p=(person:Person)-[STAYS]->(place:Place) RETURN p

MATCH p=(person:Person) RETURN p

I could not find a query where I get all of these.

1 Answer
1

You need to put the relations into optional matches, like this:

MATCH (person:Person)
OPTIONAL MATCH (person)-[:VISITED]->(monument)
OPTIONAL MATCH (person)-[:STAYS]->(place)
return person, place, monument


Otherwise, neo4j treats the relations in your query 1) as required, that's why 'Ron' will be the only result.

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