Hi alex, Some interesting suggestions, As far as I'm aware the Neo4j reference node is needed to display graphs in neoclipse, That is the only reason i would use a reference node.
The last test that was failing should work if you use the LuceneFulltextQueryIndexService<http://components.neo4j.org/neo4j-index/apidocs/org/neo4j/index/lucene/LuceneFulltextQueryIndexService.html> fulltextIndex = new LuceneFulltextQueryIndexService(gds); ElasticSearch looks really good. How would you integrate ElasticSearch with neo4j? cheers Paddy 2010/9/3 Alexandru Popescu ☀ <[email protected]> > On Friday, September 3, 2010, <[email protected]> > wrote: > > 1. They are "durable" but not "permanent", in the sense that if a node > > is deleted, its ID will be re-used, unlike autoincremented keys in a > > database, which are typically not re-used. Perhaps a poor choice of > > words. > > > > In fact if I'm reading this right, they are both durable and > permanent: as long as the node exist it will always be associated with > that ID. The only caveat is that IDs can be reused once their initial > node was purged from the system. > > This is a very important aspect as I can imagine many systems that can > use a small subset of the existing nodes as entry points. Basically by > using the cached IDs you'll be able to get to these without the need > of using indexing/traversals. > > > > 3. Third parameter = value of the K-V pair you're using to index the > > node. > > > > I figured that out myself, but I still believe that the new method > I've suggested would be welcome. Real question is: how many time you > store a set of properties in the node, but want to index it by a > completely unrelated/not persistent value? I'd speculate that this > scenario is very very rare. > > > > > 4. The reference node is merely one approach to a graph structure. > > You can have any number of standalone nodes. Reasonable to allow > > deleting the default reference node, though it might be a good idea to > > make this a configurable option on DB creation. > > > > If the "reference node" is not mandatory then why creating it by > default? If you take as a reference the most well known hierarchical > model, the FS, there it makes a lot of sense to have a root node > (which is undeletable). But as I read this and noticed from the tests, > the Neo4j "reference node" serves no purpose at all. > > > > > > > 5/6. Haven't done much with Lucene yet, about to get started soon. > > Please keep sharing your experiences. Considering whether or not to > > use SOLR, also. > > > > I want to keep things as simple as possible, so for my current > experiments I'll not look beyond what is already available in Neo4j. > This aside, if I'd be to look into using a 3rd party indexing tool, my > first option would be ElasticSearch (disclaimer: I do know the lead > developer of ElasticSearch and his experience in indexing tools). > > I hope others will jump in and comment/answer on my suggestions and > questions. > > Thanks, > > :- alex > > > > > > > -------- Original Message -------- > > Subject: [Neo4j] API Questions and a bit more > > From: Alexandru_Popescu_â <[1][email protected]> > > Date: Fri, September 03, 2010 4:53 am > > To: [2][email protected] > > Hi all, > > Last night I had some time to play with Neo4j (1.1) API. I do have a > > couple of questions and comments that I'd like to share with you: > > 1. The documentation I've found mentions that `Node` IDs are not > > "permanent". I'm wondering why are IDs exposed them? > > 2. I was surprised to see a `Node`.delete() failing. The reason was it > > had relationships. I think adding a method `Node`.delete(boolean > > force) would > > make code much easier. The method would automatically: > > - remove all relationships > > - clean up indexes > > Note 1: I've been able to implement locally such a method in an > > utility class and it seems to work without any problems. Anyways > > another thing that I've found a bit weird was that I had to use > > separate reference to GraphDatabaseService and 2 IndexServices (a > > simple LuceneIndexService and a LuceneFulltextIndexService). I think > > it would once again simplify a lot of things if these IndexServices > > would be available through the GraphDatabaseService API. > > Note 2: as far as I can say this would be a non-breaking API change > > 3. I was a bit confused when trying to index a new node as I wasn't > > sure what's the last parameter in `IndexService.index(Node, String, > > Object)`. > > While understanding the flexibility this would offer, I'd speculate > > that most of the time you'd want to actually index the values set in > > the Node, so an > > API like `IndexService.index(Node, String... properties)` would once > > again simplify a lot of code. > > Note: as far as I can say this is a non-breaking API change > > 4. Q: while running my tests, I've tried to clean up data behind. Thus > > I've discovered that I can delete the so called "reference node". That > > made me wonder: if it is a default node, why allowing to be deleted? > > 5. Q: by looking at the documentation I couldn't figure out for sure > > if you are allowed to use both a LuceneIndexService and > > LuceneFullIndexService. My tests seem to work while using both, but > > I'm not sure if that is what's suppose to happen. > > 6. I've run into a test where LuceneFullIndexService doesn't seem to > > return what I'm expecting. But I'm not a Lucene specialist so maybe > > I'm doing something wrong. Code below: > > package com.mypopescu.neo4j; > > import org.junit.AfterClass; > > import org.junit.BeforeClass; > > import org.junit.Test; > > import org.neo4j.graphdb.GraphDatabaseService; > > import org.neo4j.graphdb.Node; > > import org.neo4j.graphdb.Relationship; > > import org.neo4j.graphdb.Transaction; > > import org.neo4j.index.IndexHits; > > import org.neo4j.index.IndexService; > > import org.neo4j.index.lucene.LuceneFulltextIndexService; > > import org.neo4j.kernel.EmbeddedGraphDatabase; > > import [3]java.io.File; > > import static [4]org.hamcrest.CoreMatchers.is; > > import static org.junit.Assert.assertThat; > > /** > > * @author Alex Popescu > > * @since Sep 3, 2010 > > */ > > public class LuceneFulltextIndexServiceTest { > > static GraphDatabaseService gds; > > static IndexService fulltextIndex; > > @BeforeClass > > public static void setup() { > > gds= new EmbeddedGraphDatabase("data/neodb/neodb-tmp"); > > fulltextIndex= new LuceneFulltextIndexService(gds); > > } > > @Test > > public void fullTextIndex() { > > Transaction tx= gds.beginTx(); > > try { > > Node ndOne= gds.createNode(); > > ndOne.setProperty("ft", "some text in here to be fully indexed"); > > fulltextIndex.index(ndOne, "ft", ndOne.getProperty("ft")); > > Node ndTwo= gds.createNode(); > > ndTwo.setProperty("ft", "some other text in there not to > > be indexed uniquely"); > > fulltextIndex.index(ndTwo, "ft", ndTwo.getProperty("ft")); > > tx.success(); > > } > > finally { > > tx.finish(); > > } > > IndexHits<Node> ns= fulltextIndex.getNodes("ft", "some text"); > > assertThat(ns.size(), is(2)); > > for(Node n : ns) { > > System.out.printf("Full text n...@%s: {%s}%n", n.getId(), > > n.getProperty("ft")); > > } > > ns= fulltextIndex.getNodes("ft", "some text indexed"); > > assertThat(ns.size(), is(2)); > > for(Node n : ns) { > > System.out.printf("Full text n...@%s: {%s}%n", n.getId(), > > n.getProperty("ft")); > > } > > ns= fulltextIndex.getNodes("ft", "indexed text"); > > assertThat(ns.size(), is(2)); > > for(Node n : ns) { > > System.out.printf("Full text n...@%s: {%s}%n", n.getId(), > > n.getProperty("ft")); > > } > > ns= fulltextIndex.getNodes("ft", "uniquely text"); > > assertThat(ns.size(), is(1)); > > for(Node n : ns) { > > System.out.printf("Full text n...@%s: {%s}%n", n.getId(), > > n.getProperty("ft")); > > } > > // THIS ONE IS FAILING > > ns= fulltextIndex.getNodes("ft", "uniquely OR text"); > > assertThat("actually it should find 2", ns.size(), is(2)); > > for(Node n : ns) { > > System.out.printf("Full text n...@%s: {%s}", n.getId(), > > n.getProperty("ft")); > > } > > } > > @AfterClass > > public static void shutdown() { > > fulltextIndex.shutdown(); > > gds.shutdown(); > > } > > } > > 7. I was wondering what is the best way to clean up a temporary test > > database. > > My apologies in advance for such a long email (I usually don't do > > this). And thanks in advance for all your answers, > > :- alex > > _______________________________________________ > > Neo4j mailing list > > [5][email protected] > > [6]https://lists.neo4j.org/mailman/listinfo/user > > > > References > > > > 1. mailto:[email protected] > > 2. mailto:[email protected] > > 3. http://java.io/ > > 4. http://org.hamcrest.CoreMatchers.is/ > > 5. mailto:[email protected] > > 6. https://lists.neo4j.org/mailman/listinfo/user > > > _______________________________________________ > Neo4j mailing list > [email protected] > https://lists.neo4j.org/mailman/listinfo/user > _______________________________________________ Neo4j mailing list [email protected] https://lists.neo4j.org/mailman/listinfo/user
