Can't figure out Cypher queries even when I duplicate what is in the docs.

[bytor99999]

I think we need more examples in the samples or docs on how to write Cypher Queries in our Spring Data Neo4J Repositories. The sections that talk about putting @Query on your methods is too sparse.

Here is my query as it stands now

@Query("start user=node: " +
    	"match (user)-[:FRIEND]->(friend)-[:FRIEND]->(friendOfFriend) " +
    	"return friendOfFriend " +
    	"order by count(*) desc")
    public Page<User> findFriendsOfFriends(@Param("node") User user, Pageable pageable);

And my current exception is

Caused by: org.neo4j.cypher.SyntaxException: `=' expected but `)' found

I have tried many different versions based on stuff in the docs from

start movie=node:Movie(title='Matrix') match (movie)<-[:ACTS_IN]-(actor) return actor.name
where I have each node in the match in parenthesis like what I have above

To trying not having parentheses because I saw this in the docs
// start person=node:__types__("className"="com...Person")
// where person.age = {0} and person.married = {1}
// return person

And tried this which I found in the docs

interface MovieRepository extends GraphRepository<Movie> {
	@Query("
	start user=node({0}) 
	match user-[:FRIEND]-friend-[r:RATED]->movie
	return movie
	order by avg(r.stars) desc, count(*) desc
	limit 10
	")
    Iterabe<Movie> recommendMovies(User me);
}

If I try

@Query("start user=node({0}) match (user)-[:FRIEND]->(friend)-[:FRIEND]->(friendOfFriend) return friendOfFriend order by count(*) desc")
    public Page<User> findFriendsOfFriends(User user, Pageable pageable);

I get a exception trace of

java.util.NoSuchElementException
	at scala.collection.TraversableLike$$anonfun$2.apply(TraversableLike.scala:372)
	at scala.collection.TraversableLike$$anonfun$2.apply(TraversableLike.scala:372)
	at scala.collection.TraversableLike$class.head(TraversableLike.scala:379)
	at org.neo4j.cypher.pipes.Pipe.head(Pipe.scala:31)
	at org.neo4j.cypher.pipes.SlicePipe.foreach(SlicePipe.scala:30)
	at org.neo4j.cypher.pipes.ColumnFilterPipe.foreach(ColumnFilterPipe.scala:35)
	at scala.collection.TraversableLike$class.map(TraversableLike.scala:194)
	at org.neo4j.cypher.pipes.Pipe.map(Pipe.scala:31)
	at org.neo4j.cypher.ExecutionResult$class.javaIterator(ExecutionResult.scala:49)
	at org.neo4j.cypher.pipes.ColumnFilterPipe.javaIterator(ColumnFilterPipe.scala:25)
	at org.neo4j.cypher.javacompat.ExecutionResult.iterator(ExecutionResult.java:51)
	at org.springframework.data.neo4j.conversion.QueryResultBuilder$1.iterator(QueryResultBuilder.java:112)
	at org.neo4j.helpers.collection.IteratorUtil.addToCollection(IteratorUtil.java:339)
	at org.springframework.data.neo4j.repository.query.GraphRepositoryQuery.createPage(GraphRepositoryQuery.java:107)
	at org.springframework.data.neo4j.repository.query.GraphRepositoryQuery.dispatchQuery(GraphRepositoryQuery.java:88)
	at org.springframework.data.neo4j.repository.query.GraphRepositoryQuery.execute(GraphRepositoryQuery.java:70)
	at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:301)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
	at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
	at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:155)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
	at $Proxy50.findFriendsOfFriends(Unknown Source)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:318)
	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:196)
	at $Proxy52.findFriendsOfFriends(Unknown Source)
	at com.perfectworldprogramming.eventgate.user.UserDBTests.testFindFriendsOfFriends(UserDBTests.java:141)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
	at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
	at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74)
	at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:83)
	at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:231)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:49)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
	at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
	at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:174)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:157)
	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:71)
	at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:202)
	at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:63)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at com.intellij.rt.execution.application.AppMain.main(AppMain.java:120)

So no luck

Will the real slim shady please stand up?

Thanks for you help

Mark

[bytor99999]

This query looks like it is working, and really isn't much different except without the [:FRIENDS] part to state the relationship name.

@Query("start user=node({0}) match user-->friends-->friendsOfFriends return friendsOfFriends order by count(*) desc")

I had to start with a small query just to get the "start" portion syntax correct with return, then added order by clause, then tried user-->friend which didn't work, then user-->friends which did work. Then just extended it out to two nodes away.

Thanks

Mark

[bytor99999]

I spoke too soon. While that query above did not cause an exception, it still wasn't returning the correct data. So now I have

@Query("start user=node({0}) " +
            "match user-[?:FRIENDS]-f-[?:FRIENDS]-fof " +
            "return fof " +
            "order by count(*) desc")
    public Page<User> findFriendsOfFriends(User user, Pageable pageable);
    
    @Query("start user=node({0}) " +
           "match user-[?:FRIENDS]-f " +
           "return f " +
           "order by f.lastName asc")
    public Page<User> findFriends(User user, Pageable page);

I had to put the specific relationship type, and that it could be there or not, because without the "?" for optional I got an exception.

With these queries above, there aren't exceptions, but no results back either even though I have data in the db that should match and return some data. I have auser which is friends with cuser, and buser is also friends with cuser, so if I search for friends of friends for auser, I should get back buser, but I get nothing in the contents.

Same with findFriends query. If I try to find cuser's friends I should get two Users back a and b user. But again I get nothing in the contents. empty.

What am I doing wrong?

Thanks

Mark

[MichaelHunger]

Mark,

so you figured it out on your own, sorry for the late reply.

In the first query you missed the index part : start user = node:Users(login={0}) ...
general syntax is: node:<indexName>(<indexKey>=<indexValue>) ...

for your query that don't return something - cypher matches subgraphs if it doesn't find any subgraphs it returns an empty result, which is then causing the issue, can you file a bug on JIRA for the java.util.NoSuchElementException.

If you leave off relationship-types as you did with the FRIEND it takes any arbitrary outgoing relationship and uses that and returns the node at the end of it (which might not what you intended).

If you have queries that should result in a single value (or null) you should either use optional relationships like me-[?:FRIEND]->friend which return null or have them result in a collection object (which might then be empty). This will be alleviated in the future so that empty results also result in a null value for a single result.

In your last post you used FRIEND_S_ and in the others FRIEND, perhaps that's why it didn't find any results?

Cheers

Michael

[bytor99999]

Thanks.

"In your last post you used FRIEND_S_ and in the others FRIEND, perhaps that's why it didn't find any results?"

That's what happens when you stop using your own constant that has the correct "FRIEND" String assigned to it. But I did remove the constant remove a variable from the equation as a possible reason why my query wasn't working.

Thanks again.

Mark

[bytor99999]

I commented on the 196? I am still getting the exception with SDN 2.0.1.RELEASE. It is starting to create an issue in my app. The other one I could work around. This one affects a lot of areas in my code for the web app. I could put all these try catches around everything but, I try to avoid any try-catch anywhere in my code. Or I could just create an aspect class to do that part. That would be cleaner here.

Mark

[MichaelHunger]

Could you please show mvn dependency:tree to make sure that you have the latest neo4j/cypher versions?

Also you may share your app privately with me, so that I can have a look at the issue.

Michael

[bytor99999]

Which Neo4j/Cypher versions are you expecting. The Jira only talked about the SDN version needed.

I am still on Neo4j 1.5

Don't need to run tree on it, I got IntelliJ.

Mark

[bytor99999]

Upgraded to Neo4j 1.6 and it now works, no Exception. Thanks!

Although I did have to delete my database because it was based on 1.5. It gave me a message about putting something about auto-update=true somewhere, but it didn't state exactly where. I am using the Embedded Neo4J with SDN, so the only config files I have are Spring config files. Spring Roo did create a neo4j.properties file with the location property in it, and I have added allow_store_upgrade=true also in the .properties file, but it didn't upgrade my database, I had to delete the database.

Where can I put allow_store_upgrade=true so that in the future when there is actually real data in the database that I don't have to delete it and lose all that data?

Thanks

Mark

[MichaelHunger]

You just pass it in to your embedded graphdb config as stated in the docs

http://static.springsource.org/sprin.../html/#d0e3354

<context:annotation-config/>

<bean id="graphDatabaseService" class="org.neo4j.kernel.EmbeddedGraphDatabase"
        destroy-method="shutdown">
    <constructor-arg index="0" value="target/config-test"/>
    <constructor-arg index="1">
        <map>
            <entry key="allow_store_upgrade" value="true"/>
        </map>
    </constructor-arg>
</bean>

<neo4j:config graphDatabaseService="graphDatabaseService"/>