Specifying the uniqueness of paths is a planned feature of cypher. So right now we have to ascertain that no node is a duplicate in the path. There is an ALL predicate that must hold true for all elements of a collection (which a path is). And with filter you can extract the elements of … Read more
Update 01/10/2013: Came across this in the Neo4j 2.0 reference: Try not to use optional relationships. Above all, don’t use them like this: MATCH a-[r?:LOVES]->() WHERE r IS NULL where you just make sure that they don’t exist. Instead do this like so: MATCH a WHERE NOT (a)-[:LOVES]->() Using cypher for checking if relationship doesn’t … Read more
The browser is telling you that: It is handling your query by doing a comparison between every Gene instance and every Chromosome instance. If your DB has G genes and C chromosomes, then the complexity of the query is O(GC). For instance, if we are working with the human genome, there are 46 chromosomes and … Read more
There are several options to do this. I’ll illustrate some of the more popular ones. Named Graphs / Quads In RDF, named graphs are subsets of an RDF dataset that are assigned a specific identifier (the “graph name”). In most RDF databases, this is implemented by adding a fourth element to the RDF triple, turning … Read more