Sounds like a pretty easy SQL query, though. ;-)
Actually the "random sampling" aspect definitely throws a complication into the requirements. I can't even picture how to achieve that in Neo without first obtain some (large) set of nodes and using a randomizer to select from the set/array. Iterating on getAllNodes and stopping after "n" matches wouldn't meet the "random" requirement. It might be helpful to better understand the application/domain requirements and maybe there are alternative ways to achieve the same results. -------- Original Message -------- Subject: Re: [Neo4j] Querying for nodes that have no relationhip to a specfic node From: Vitor De Mario <[1][email protected]> Date: Tue, July 27, 2010 8:24 pm To: Neo4j user discussions <[2][email protected]> If this is feasible in Alberto's application, you have to consider that you will be creating a complete graph, and for such a graph with n nodes, you'll have O(n^2) relationships. This can grow really, really fast. Besides, it would turn the insertion of a new node into a potentially slow operation, as you would need to assign the "absence" relationship to every existing node. []'s Vitor On Tue, Jul 27, 2010 at 8:51 PM, Niels Hoogeveen <[3][email protected]>wrote: > > Is it possible to encode the absence of a relationship with a relationship > in your application? > > > Date: Tue, 27 Jul 2010 18:52:10 +0100 > > From: [4][email protected] > > To: [5][email protected] > > Subject: [Neo4j] Querying for nodes that have no relationhip to a specfic > node > > > > Hi, > > > > I'm considering using neo4j for a current project I'm working on. > > > > I need to do the following periodically (e.g. daily): > > * step 1: for every node, let's call it A, I need to pick n other > > nodes randomly that fullfill certain attributes and have no > > relationship to A. > > * step2: For each of those nodes and A, I calculate some value and > > store it within the relationship. > > > > Regarding step 1, from what I've read, it seems there is no way of > > querying nodes that have no relationship to a specific node. Of course > > I could query all the nodes of the database that fullfill certain > > attributes, store them within a variable, then query all relationhips > > for node A and then substract those nodes from the array variable. But > > I think this approach won't work very well as the amount and density > > of relationships gets higher... > > > > Do you have any recommendations? Can you suggest another strategy? > > Perhaps there is a way of making that query? > > > > Any help of appreciated. > > Alberto. > > _______________________________________________ > > Neo4j mailing list > > [6][email protected] > > [7]https://lists.neo4j.org/mailman/listinfo/user > > _________________________________________________________________ > New Windows 7: Simplify what you do everyday. Find the right PC for you. > [8]http://windows.microsoft.com/shop > _______________________________________________ > Neo4j mailing list > [9][email protected] > [10]https://lists.neo4j.org/mailman/listinfo/user > _______________________________________________ Neo4j mailing list [11][email protected] [12]https://lists.neo4j.org/mailman/listinfo/user References 1. mailto://[email protected]/ 2. mailto://[email protected]/ 3. mailto://[email protected]/ 4. mailto://[email protected]/ 5. mailto://[email protected]/ 6. mailto://[email protected]/ 7. https://lists.neo4j.org/mailman/listinfo/user 8. http://windows.microsoft.com/shop 9. mailto://[email protected]/ 10. https://lists.neo4j.org/mailman/listinfo/user 11. mailto://[email protected]/ 12. https://lists.neo4j.org/mailman/listinfo/user _______________________________________________ Neo4j mailing list [email protected] https://lists.neo4j.org/mailman/listinfo/user
