cypher query connundrum

[Eugen Paraschiv]

Hi,
I'm working with Spring Data Neo4J, Neo4j 1.6.1 and the following model:
@Indexed(indexName = "locationsindex")
public class Location {
    @GraphId
    private Long id;

    private float latitude;
    private float longitude;
    ...
}
and I'm trying to write a Cypher query like:
@Query("...")
Location findByLatAndLong(final float latitude, final float longitude);
I have tried several options and nothing seems to work; I'm now thinking that perhaps I should select the node by an index query (because I need to check both latitude and longitude).
Any help is appreciated.
Thanks.
Eugen.

[Peter Neubauer]

Yes,
That sounds like a plan. Have you checked out the spatial support, with a Well Known Text property to hold the points?

[Michael Hunger]

You find some docs here: 

http://static.springsource.org/spring-data/data-graph/snapshot-site/reference/html/#d0e2153

Michael

[Eugen Paraschiv]

Sorry, I shouldn't have used Location(lat,lng) necessarily - it can be any other entity with two floats (I'm not using the spring data geo support at the moment). So essentially it's not related to geospatial stuff - just a general entity and an general query retrieving it by 2 fields.
I'm not exactly sure about the documentation helping all that much on this - what exactly is the example query I should be looking at?
Thanks.
Eugen.

[Jacob Hansson]

Could you include an example of a query you have tried, and the result you expected?

Like you mention, you need an index lookup (or a node id) for Cypher to start from. It currently does not let you look globally for unindexed properties.

I'm not super familiar with the spring integration.. does the @indexed in the beginning of the entity mean all attributes are indexed?

If so, you should be able to do something like:

START nodes=node:locationsIndex(latitude=100, longitude=200)
RETURN nodes

Sent from my phone, please excuse typos and brievety.

[Michael Hunger]

Eugen,

you should always be able to do something like:

Location findByLatitudeAndLongitude(final float latitude, final float longitude);

Which auto-generates the query you need. (It uses the where-clause to filter for the entities).

You might index the properties (at least one, there is still a bug with indexing two) then the query would use that to look up.

Michael

[Eugen Paraschiv]

Right, I had some trouble with the autogenerated queries (posted about it a while back) so I didn't even try - it works well, thanks. Is there a way to see the exact query that gets generated?
On the query you suggested, that's fine if you have the values (100 and 200) but if you have arguments:

Location findByLatAndLong(final float latitude, final float longitude);

then using {0} and {1} INSIDE the query:
@Query("START location=node:locationsindex(\"latitude:{0} AND longitude:{1}\") RETURN location")
doesn't work.
Thanks.
Eugen.

[Michael Hunger]

Eugen, you will have to construct the lucene index query outside and pass it in as an parameter:

String locationQuery = String.format("latitude:%d AND longitude:%d",lat,lon);

@Query("START location=node:locationsindex({0}) RETURN location")

findByLocationQuery(String locationQuery)

HTH

Michael

[Eugen Paraschiv]

Yeah, I thought about doing that - I just wanted to make sure there's no other way.
Thanks for all the feedback and help.
Eugen.