[neo4j] Building up the HelloWorlds example with tags property

[Jackal789]

Hi all,

I'm new to graph databases and spring, trying to learn from the examples on git. I downloaded the HelloWorlds example and got everything working. what I'd like to do is add a tags property to Worlds, so one could tag Earth is 'blue', 'water', 'civilization', etc. I added some tags to every world. What i'd like to be able to do is search by tag and get all worlds.

so I added to World; I put set by varargs in constructor

@Indexed(indexName = "tags-index")
    private Set<String> tags = new HashSet<String>(); 

And added method to WorldRepositoryImpl

public Iterable<World> findResourcesByTag(String tag) {
        return worldRepository.findAllByPropertyValue("tags-index", "tags", tag);
    } 

I added call to app

Iterable<World> bWorlds = repo.findResourcesByTag("blue"); 

but it returns nothing, when I started stepping thru but couldn't really follow along. I thought trying to make it a relationship but what would the end node be? A tag class didn't seem efficient, but maybe i was wrong? Ideas?

Thanks for any advise!

[MichaelHunger]

Good idea but it works a bit differently.

You can store the tags as property on the world but it makes much more sense to store them as nodes. (And you cannot index collection attributes - yet - if you think this is important please file an JIRA issue at http://spring.neo4j.org/issues).

The tag as node is not inefficient but the way graphs work.

so you create

@NodeEntity
public class Tag {
  @Indexed(unique = true) String name;
}

@NodeEntity
public class World {
   @RelatedTo
   Set<Tag> tags;
}  

// and then add the tags either by adding them to the set or using template.createRelationshipBetween

HTH

Michael

[Jackal789]

Hi Michael,

Thanks for clarifying I should have implemented it that way the first time around.

Says a lot that you're here answering questions as I have been watching your presentations and reading your Good Relationships tutorial.

Thanks!

Good idea but it works a bit differently.

You can store the tags as property on the world but it makes much more sense to store them as nodes. (And you cannot index collection attributes - yet - if you think this is important please file an JIRA issue at http://spring.neo4j.org/issues).

The tag as node is not inefficient but the way graphs work.

so you create

@NodeEntity
public class Tag {
  @Indexed(unique = true) String name;
}

@NodeEntity
public class World {
   @RelatedTo
   Set<Tag> tags;
}  

// and then add the tags either by adding them to the set or using template.createRelationshipBetween

HTH

Michael