Hi,
I finally found a workaround, by using :
@Query(value = "MATCH (n:Community) WHERE id(n)=({id}) RETURN count(n)")
public Long count(@Param("id") Long id);
and an external method that converts the result of the count(Long id) to a
boolean.
Grégoire
Le lundi 17 mars 2014 15:59:05 UTC+1, Grégoire Colbert a écrit :
>
> Hi Michael,
>
> Following your comment at https://jira.spring.io/browse/DATAGRAPH-438 :
> is there a way to override the exists() method before the issue is solved?
> That is, is there a way to make this request:
>
> match (n:Community) where id(n)={id} return count(n) > 0
>
> return a boolean when there is zero node returned?
>
> Thanks!
> Grégoire
>
> Le jeudi 6 mars 2014 08:00:19 UTC+1, Michael Hunger a écrit :
>>
>> Great question.
>>
>> You're not expected to override exists.
>>
>> It should actually just work. I would appreciate a JIRA issue with the
>> content of this email. Not sure I understand it all, so a test-project with
>> a failing unit-test would be awesome.
>>
>> Thanks a lot
>>
>> Michael
>>
>> I think most sense would make (this doesn't work yet I think), to coerce
>> the numeric result to a boolean
>>
>> @Override
>> @Query(value = "match (n:Community) where id(n)={id} return count(n)")
>> public boolean exists(@Param("id") Long id);
>>
>>
>> Am 05.03.2014 um 17:58 schrieb Grégoire Colbert <[email protected]>:
>>
>> Hi,
>>
>> I'm trying to override the "boolean exists(Long)" function in my
>> CrudRepositories interfaces, and I think I have found an inconsistency in
>> Cypher about the "return" clause.
>>
>> The method I want to add to "CommunityRepository" is :
>>
>> @Override
>> @Query(value = "match (n:Community) where id(n)={id} return count(n)
>> > 0")
>> public boolean exists(@Param("id") Long id);
>>
>> What happens is this :
>> - if the node whose "id" is given carries the label ":Community", then
>> this request will return a boolean "true", which is the expected behaviour.
>> - if the node doesn't carry the ":Community" label (for example it
>> carries ":Institution"), then the request will return "0 row" which is not
>> a boolean value.
>>
>> So the bug is that "return count(n) > 0" is ignored when there is no node
>> returned.
>>
>> Some help would be really appreciated as I don't know how to solve my
>> original issue involving the "exists" function.
>>
>> Thanks,
>> Grégoire
>>
>> Le mercredi 5 mars 2014 16:27:48 UTC+1, Grégoire Colbert a écrit :
>>>
>>> Hi,
>>>
>>> I have an abstract class "OrganisationNode" containing a "@GraphId id"
>>> field.
>>>
>>> I have several concrete classes extending OrganisationNode, for example
>>> "InstitutionNode" or "CommunityNode". None of them have a @GraphId field.
>>> If I put another "@GraphId id" field on InstitutionNode, I get the
>>> following error "Attempt to add id property private java.lang.Long
>>> eu.ueb.acem.domain.beans.rouge.neo4j.OrganisationNode.id<http://eu.ueb.acem.domain.beans.rouge.neo4j.organisationnode.id/>but
>>> already have property private java.lang.Long
>>> eu.ueb.acem.domain.beans.rouge.neo4j.InstitutionNode.id<http://eu.ueb.acem.domain.beans.rouge.neo4j.institutionnode.id/>registered
>>> as id. Check your mapping configuration!"
>>>
>>> However, this seems ok at first, because each of my DAOs (e.g.
>>> InstitutionDAO, CommunityDAO, etc) contain a CrudRepository instance
>>> specific to a given concrete class. It can create nodes and they have the
>>> good labels, e.g. if I call InstitutionRepository.create("my new
>>> institution"), the resulting node will have the labels : "Organisation",
>>> "Institution" and "_Institution". That's exactly what I want.
>>>
>>> The problem is that CrudRepository#exists returns true, even if I mix
>>> the concrete classes. For example, if I call
>>> InstitutionRepository#exists(id of a CommunityNode), it returns true! The
>>> same thing happens with CommunityRepository#exists(id of an
>>> InstitutionNode).
>>>
>>> It seems that the @GraphId concerns the OrganisationNode and that the
>>> "exists" method doesn't care about the type associated with the
>>> CrudRepository. I would find logical the following results :
>>> - InstitutionRepository#exists(id of a InstitutionNode) to return true
>>> - InstitutionRepository#exists(id of a CommunityNode) to return false
>>>
>>> Is that a bug? Or is that how it is supposed to work, and should I
>>> overwrite the "exists" method?
>>>
>>> Thanks!
>>>
>>> Grégoire
>>>
>>
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