Spring Data Neo4j pass relationship name as parameter-CodePudding

Is it possible to pass relationship name as parameter?

I'm trying to do this with SpEL:

@Query("MATCH (l:Location:Requirable {id: $locationId})<-[rld::#{#relationshipName}]-(d:Decision {id: $decisionId}) "  
        "DETACH DELETE rld")
void detachLocation(@Param("locationId") Long locationId, @Param("decisionId") Long decisionId, @Param("relationshipName") String relationshipName);

but it fails with the following error:

org.springframework.dao.InvalidDataAccessResourceUsageException: Cypher execution failed with code 'Neo.ClientError.Statement.SyntaxError': Invalid input '$': expected an identifier (line 1, column 52 (offset: 51))
"MATCH (l:Location:Requirable {id: $locationId})<-[:$spel_expr0]-(d:Decision {id: $decisionId}) OPTIONAL MATCH (l)-[rdt:CONTAINS]->(t:Translation:Requirable) WHERE ($iso6391 IS NOT null AND t.iso6391 = $iso6391) RETURN l, rdt, t"
                                                    ^.; nested exception is org.neo4j.ogm.exception.CypherException: Cypher execution failed with code 'Neo.ClientError.Statement.SyntaxError': Invalid input '$': expected an identifier (line 1, column 52 (offset: 51))

I user Spring Data Neo4j 5.3.9.RELEASE OGM version

is it possible or no? If so, could you please show how.

CodePudding user response：

It's not exactly what you were looking for, but I would consider simple WHERE condition (if you're not working on really huge datasets and you're not really care about few more db hits).

WHERE type(r) = $relationshipName

Here query which should work:

@Query("MATCH (l:Location:Requirable {id: $locationId})<-[rld]-(d:Decision {id: $decisionId}) WHERE type(rld) = $relationshipName DETACH DELETE rld")
void detachLocation(@Param("locationId") Long locationId, @Param("decisionId") Long decisionId, @Param("relationshipName") String relationshipName);

CodePudding user response：

The answer is no. Relationship types and Node Labels cannot be parameterized in Cypher as of now. Either you can go with @degath answer. Or construct the query using strings, something like this:

public static final String query = "MATCH (l:Location:Requirable {id: $locationId})<-[rld:REL_TYPE]-(d:Decision {id: $decisionId}) DETACH DELETE rld"

String finalQuery = query.replaceAll("REL_TYPE", relationshipName);

Then you can pass this generated query to an APOC function. Something like this:

@Query("CALL apoc.cypher.run($query, {locationId: $locationId, decisionId: $decisionId}) yield value")
void detachLocation(@Param("locationId") Long locationId, @Param("decisionId") Long decisionId, @Param("query") String query);

Note this is not tested.