I had an answer for this also, but see that Andreas and Anders have both
answered with the two mechanisms I had tried:
- lucene
- custom index
But I thought I'd add a little on the custom index idea, because I think
that can also provide fast sorting, if you are usually requiring answers in
the same order every time. Your index would be built as a simple chain of
nodes, sorted in the order you want, and optionally done as a tree structure
for fast selections on very large datasets. You can add to the index as you
add data to your dataset, so there is no need for re-indexing. However, this
assumes a fixed sort order. If you want to change the sort order between
many different properties and directions, then this is not a good solution.
Unfortunately I have not done performance and memory comparisons between
this and the lucene approach.
On Wed, Nov 18, 2009 at 8:44 AM, Andreas Ronge <andreas.ro...@jayway.se>wrote:
> Hi
>
> There is also another alternative available in Neo4j.rb (the JRuby
> Neo4j wrapper) by using lucene.
> In Neo4j.rb you have access to the full lucene query language.
>
> Examples:
> Person.find(:name => 'kalle').sort_by(:salary)
> Person.find("name:kalle AND salary:[10000 TO
> 30000]").sort_by(Desc[:salary, :country])
>
> Cheers
> /Andreas
>
> On Wed, Nov 18, 2009 at 1:07 AM, Anders Nawroth
> <and...@neotechnology.com> wrote:
> > Hi!
> >
> >> I want to use neo4j to build a prototype of a social network
> >> application because of his graph structure and I have a problem when I
> >> try to filter and sort the nodes resulted from traversal.
> >> For example - I want to show a list with members of a group filtered
> >> by some property and ordered by another; I don't find any optimization
> >> for filter/sort operations in neo.
> >>
> >
> > Regarding filtering, my first thought goes to using ReturnableEvaluator
> > when using a Traverser to find nodes. The ReturnableEvaluator decides
> > which nodes should go into the result. If you need to block traversal
> > beyond specific nodes or at a specific depth, have a look at the
> > StopEvalutor as well. You'll find some hints on searching in Neo4j here:
> > http://wiki.neo4j.org/content/Design_Guide#Search
> > The evaluators are described in the core APIdocs:
> > http://api.neo4j.org/current/
> >
> > The structure of the node space can also be used to implement your very
> > own indexing/search stuff. You can find a practical example of that here:
> > http://wiki.neo4j.org/content/IMDB_Search_Engine
> >
> > For sorting, the simplest option is to do it in your own code.
> >
> > HTH!
> >
> >
> > /anders
> >> Do you have some implementation suggestions? Do you think that neo4j
> >> can be used for this kind of job?
> >>
> >> Thank you.
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> >>
> >
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