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On Wednesday, January 8, 2014 6:17:18 PM UTC+5:30, Gwendal Mousset wrote:
>
> Hello,
>
> I have an issue with cypher request using collect() function.
> I'm using spring-data-neo4j 3.0.0-M1 and Neo4j 2.0.0-M06.
>
> In my data model i have Category nodes.
> Each category can have subcategories.
> I want to retrieve the top categories list with the associated
> subcategories.
>
> *Categ3* -- IS_SUBCATEGORY_OF --> *Categ1* <-- IS_SUBCATEGORY_OF --
> *Categ2*
>
> *My request:*
>
> MATCH (cat:Category)
> WITH cat
> MATCH (cat)<-[?:IS_SUBCATEGORY_OF]-(subCat:Category)
> WHERE NOT cat-[:IS_SUBCATEGORY_OF]->()
> RETURN cat as category, collect(subCat) as subCategories
>
>
> The query result is exactly what i expect in the console:
>
>
> +--------------------------------------------------------------------------------------------------------------------------------------------------------+
> | category | subCategories
>
> |
>
> +--------------------------------------------------------------------------------------------------------------------------------------------------------+
> | Node[128]{id:"e9c27555f46c4acdb29c8d0e89814467"} | []
>
> |
> | Node[176]{id:"78f7c907068c4e1abd018fe560c2c03a"} | []
>
> |
> | Node[134]{id:"e362b9c05a8f41f0aee877f914f2658f"} | []
>
> |
> | Node[136]{id:"7b3d58a89ebd4010964004d58e962526"} | []
>
> |
> | Node[118]{id:"3378af0b1f54405fb7ab2970cba5bff3"} |
> [Node[34]{id:"d10cc4418c914c1281f7183da8109a4f"},Node[46]{id:"b3012831db924c22829a0335df2e90d1"}]
>
> |
> | Node[130]{id:"e3e290b4d2c648b3a6a7d0fe8da461ef"} | []
>
> |
> | Node[138]{id:"eb828c120cb248c2a5baa92734e39b91"} | []
>
> |
> | Node[132]{id:"057aeb6913474454a329571b9a266305"} | []
>
> |
> | Node[126]{id:"2671039fa6f24f5b806df682c238d1c4"} |
> [Node[120]{id:"48bc7f2b34db49bfb40936864a7a4a80"},Node[122]{id:"373d94527286482fb8c807aee90d7f5e"}]
>
> |
>
> +--------------------------------------------------------------------------------------------------------------------------------------------------------+
>
>
> *My QueryResult interface:*
>
> @QueryResult
> public interface CategoryWithSubCategories {
>
>
> /**
> *
> * @return A category.
> */
> @ResultColumn("category")
> CategoryDAO getCategory();
>
> /**
> *
> * @return The subcategories.
> */
> @ResultColumn("subCategories")
> Iterable<CategoryDAO> getSubCategories();
> }
>
> *My Query: *
>
> @Query("MATCH (cat:Category) "
> + "WITH cat "
> + "MATCH (cat)<-[?:IS_SUBCATEGORY_OF]-(subCat:Category) "
> + "WHERE NOT cat-[:IS_SUBCATEGORY_OF]->() "
> + "RETURN distinct cat as category, collect(subCat) as
> subCategories")
> Iterable<CategoryDAO> getAll();
>
> When i call this method, i get an exception:
>
> java.lang.RuntimeException: Cannot extract single value from Iterable
> withmore than one elements
> .
> at org.springframework.data.neo4j.conversion.DefaultConverter.
> extractSingle(DefaultConverter.java:60)
> at org.springframework.data.neo4j.conversion.DefaultConverter.
> extractValue(DefaultConverter.java:51)
> at org.springframework.data.neo4j.conversion.DefaultConverter.convert(
> DefaultConverter.java:40)
> at org.springframework.data.neo4j.support.conversion.
> EntityResultConverter.convert(EntityResultConverter.java:165)
> at org.springframework.data.neo4j.conversion.DefaultConverter.convert(
> DefaultConverter.java:36)
> at org.springframework.data.neo4j.rest.
> SpringRestGraphDatabase$SpringResultConverter.convert(
> SpringRestGraphDatabase.java:148)
> at org.neo4j.rest.graphdb.util.QueryResultBuilder$1$1.
> underlyingObjectToObject(QueryResultBuilder.java:98)
> at org.neo4j.helpers.collection.IteratorWrapper.next(IteratorWrapper.java
> :47)
> ...
> ...
>
>
> I think my code is quite similar with the exemple in documentation at
> http://docs.spring.io/spring-data/data-neo4j/docs/3.0.0.M1/reference/htmlsingle/#reference_programming-model_mapresult
>
> Please could you tell me what i'm doing wrong ?
>
> Tank you
>
>
>
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