Counting Many Paths Between Nodes In NEO4J

August 16, 2013

A parent node in a graph database can have many child nodes.

In addition to the many children, there can be many distinct and different paths to each single child node. An example of multiple paths to the same destination is to look at a subsection of Manhattan.

Small Part of Manhattan

How many ways are there to get from the intersection of West 23rd Street and Tenth Avene, to East 34th Street and Park Avenue South? You could do only one turn: go north, and turn west. Or go west and turn north. Or you could do many turns, zig-zagging your way through the streets on the grid. And those would just be the shortest paths. You could also take the long way, zig zag all the way to the south of Manhattan, and take a site seeing tour back north.

By contrast, if there is only one country road, there is often only one way to get from point A to point B.

The more nodes and connections there are, the more the possible paths there are between nodes. As I pointed out in my last post, https://rodgersnotes.wordpress.com/2013/08/12/using-neo4j-to-find-all-parents-child-paths/ the number of paths in a graph, can be many multiples more than the number of nodes, or relationships.

So, given a parent node, finding the distinct set of children can give odd results. Here are some pitfalls to be aware of.

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Listing All Child Generations of SYS.STANDARD:

start p = node:node_auto_index ( object_id = ‘1219’  )
return p     Read the rest of this entry »


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