Return only one Boolean Row in Cypher instead of Null

Question

I have a graph with nodes like 'Persons' and relationships called 'RELATION' with a dynamic type like 'BIOLOGICAL_MOTHER'.

To check if a person is in a parent-role i want to use one cypher-query that return one boolean row, instead of NULL or something else.

I use Spring Data Neo4j 4 and this is the following method in the person-repository:

@Query("OPTIONAL MATCH (child)-[r:RELATION]->(parent) " +
        "RETURN DISTINCT " +
        "CASE " +
        "WHEN id(parent)={0} AND r IS NOT NULL AND (r.type='BIOLOGICAL_MOTHER' OR r.type='BIOLOGICAL_FATHER') " +
        "THEN true " +
        "ELSE false " +
        "END")
boolean isParentRole(long id);

If i query this on a parent person, the following error returns :

More than one element in org.neo4j.helpers.collection.IterableWrapper
$MyIteratorWrapper@235ecd9f. 
First element is 'true' and the second element is 'false'

How can i use "OR" of all result-rows, to return only one row (in this case true)?

mzober mzober · Accepted Answer · 2015-10-06T10:52:26

I solve my problem with this query:

@Query("OPTIONAL MATCH (child)-[r:RELATION]->(parent) " +
        "WITH (CASE WHEN id(parent)={0} AND r IS NOT NULL " +
        "AND (r.type='BIOLOGICAL_MOTHER' OR r.type='BIOLOGICAL_FATHER') THEN true ELSE false END) as check " +
        "RETURN ANY (x in collect(check) WHERE x=true) ")
boolean isParentRole(long id);

If an easier way solve my problem, please comment.

Return only one Boolean Row in Cypher instead of Null

1 Answers