Returing the most current league in cypher

Question

I've the League node entity as below

@NodeEntity
class League
{
  private Date startDate;
}

I want to return the most recent league for which the below cypher is working fine when executed from the shell

START n=node(*) WHERE has(n.__type__) and n.__type__='com.aravind.avl.domain.League' RETURN n ORDER BY n.startDate ASC LIMIT 1

I moved this to repository as below

public interface LeagueRepository extends GraphRepository<League>
{
    @Query ("START n=node(*) RETURN n ORDER BY n.startDate DESC LIMIT 1")
    League findCurrentLeague();
}

It is giving me the below error. I believe we no need to provide the spring-data-neo4j implementation details like __type__ when using the repositories. Wondering how to correctly write the query in repository without exposing the spring-data-neo4j implementation details?

JUNIT

@Test
    public void findCurrentLeague() throws ParseException
    {
        SimpleDateFormat df = new SimpleDateFormat("dd/MM/yyyy");

        League l1 = new League();
        l1.setStartDate(df.parse("01/03/2013"));
        l1.setEndDate(new Date());
        l1.setName("in year 2013");

        League l2 = new League();
        l2.setStartDate(df.parse("01/03/2001"));
        l2.setEndDate(df.parse("01/10/2001"));
        l2.setName("in year 2001");

        repo.save(l1);
        repo.save(l2);

        League currentLeague = repo.findCurrentLeague();
        assertNotNull(currentLeague);
        assertEquals("in year 2013", currentLeague.getName());
    }

Error

Caused by: org.springframework.dao.InvalidDataAccessResourceUsageException: Error executing statement START n=node(*) RETURN n ORDER BY n.startDate DESC LIMIT 1; nested exception is org.neo4j.cypher.EntityNotFoundException: The property 'startDate' does not exist on Node[0]
    at org.springframework.data.neo4j.support.query.CypherQueryEngine.parseAndExecuteQuery(CypherQueryEngine.java:63)
    at org.springframework.data.neo4j.support.query.CypherQueryEngine.query(CypherQueryEngine.java:49)
    ... 39 more
Caused by: org.neo4j.cypher.EntityNotFoundException: The property 'startDate' does not exist on Node[0]
    at org.neo4j.cypher.internal.commands.expressions.Property.apply(Property.scala:35)
    at org.neo4j.cypher.internal.commands.expressions.Property.apply(Property.scala:29)
    at org.neo4j.cypher.internal.pipes.ExtractPipe$$anonfun$createResults$1$$anonfun$apply$1.apply(ExtractPipe.scala:37)
    at org.neo4j.cypher.internal.pipes.ExtractPipe$$anonfun$createResults$1$$anonfun$apply$1.apply(ExtractPipe.scala:35)
    at scala.collection.immutable.Map$Map1.foreach(Map.scala:118)
    at org.neo4j.cypher.internal.pipes.ExtractPipe$$anonfun$createResults$1.apply(ExtractPipe.scala:35)
    at org.neo4j.cypher.internal.pipes.ExtractPipe$$anonfun$createResults$1.apply(ExtractPipe.scala:34)
    at scala.collection.Iterator$$anon$19.next(Iterator.scala:335)
    at org.neo4j.cypher.internal.pipes.TopPipe.createResults(TopPipe.scala:45)
    at org.neo4j.cypher.internal.pipes.ColumnFilterPipe.createResults(ColumnFilterPipe.scala:37)
    at org.neo4j.cypher.internal.executionplan.ExecutionPlanImpl$$anonfun$6.apply(ExecutionPlanImpl.scala:127)
    at org.neo4j.cypher.internal.executionplan.ExecutionPlanImpl$$anonfun$6.apply(ExecutionPlanImpl.scala:125)
    at org.neo4j.cypher.internal.executionplan.ExecutionPlanImpl.execute(ExecutionPlanImpl.scala:33)
    at org.neo4j.cypher.ExecutionEngine.execute(ExecutionEngine.scala:59)
    at org.neo4j.cypher.ExecutionEngine.execute(ExecutionEngine.scala:63)
    at org.neo4j.cypher.javacompat.ExecutionEngine.execute(ExecutionEngine.java:79)
    at org.springframework.data.neo4j.support.query.CypherQueryEngine.parseAndExecuteQuery(CypherQueryEngine.java:61)
    ... 40 more
Caused by: org.neo4j.graphdb.NotFoundException: 'startDate' property not found for NodeImpl#0.

score 1 · Accepted Answer · answered Jun 17 '13 at 13:57

1

Also, the SDN entities, if they contain indexed properties, there should be indexes for these, which let's you target these nodes:

START n=node:League("name:*") RETURN n ORDER BY n.startDate? DESC LIMIT 1

HTH

answered Jun 17 '13 at 13:57

Peter Neubauer

6,311
1
21
24

This certainly improvises the solution but the limitation is that atleast one of the entity properties should be indexed. – Aravind Yarram Jun 18 '13 at 02:13

score 0 · Answer 2 · answered Jun 14 '13 at 04:52

0

Do you have the property startDate on every node? The exception indicates:

Caused by: org.neo4j.cypher.EntityNotFoundException: The property 'startDate' does not exist on Node[0]
    at org.neo4j.cypher.internal.commands.expressions.Property.apply(Property.scala:35)

and it looks like it's complaining about the reference node.

Since you're starting at all nodes using node(*) it's probably picking up the reference node. If you don't need it then you might be able to get rid of it, or, if you don't have startDate anyway on all nodes, maybe modify your query to:

START n=node(*) RETURN n ORDER BY n.startDate? DESC LIMIT 1

answered Jun 14 '13 at 04:52

Luanne

19,145
1
39
51

But how to restrict the query to only "League" nodes. With direct cypher, I can use the __type__ property added by spring-data-neo4j but I doesn't want to use it as I think there is a better way when using spring Repositories. – Aravind Yarram Jun 14 '13 at 04:59
Sorry, then I misunderstood your question and thought you had issues with the exception thrown. I am not even sure you can do that type of restriction using Cypher directly but within Spring (unless you're on 2.0 using labels). I don't use Spring so unable to help there, sorry – Luanne Jun 14 '13 at 05:53

Returing the most current league in cypher

2 Answers2