How does "gds.graph.project" actually work in Neo4j?

Question

While practicing in neo4j online course-Neo4j Graph Data Science Fundamentals, I'm confused about the following course example:

First, create the graph projection.

CALL gds.graph.project('proj',
    ['Person','Movie'],
    {
        ACTED_IN:{orientation:'UNDIRECTED'},
        DIRECTED:{orientation:'UNDIRECTED'}
    }
);

Then we can run Dijkstra’s shortest path.

MATCH (a:Actor)
WHERE a.name IN ['Kevin Bacon', 'Denzel Washington']
WITH collect(id(a)) AS nodeIds
CALL gds.shortestPath.dijkstra.stream('proj', {sourceNode:nodeIds[0], TargetNode:nodeIds[1]})
YIELD sourceNode, targetNode, path
RETURN gds.util.asNode(sourceNode).name AS sourceNodeName,
    gds.util.asNode(targetNode).name AS targetNodeName,
    nodes(path) as path;

Question

Regarding gds.graph.project my understanding is that it creates a subgraph (subset) from the original graph.

However, in the creation of this subgraph, there are no nodes with the Actor label. So why is it possible to execute MATCH (a:Actor) when performing the Dijkstra algorithm?

cybersam · Accepted Answer · 2023-05-25 07:53:27Z

4

The MATCH (a:Actor) clause is querying the full database, not the GDS projection ('proj'). Only the procedures whose names start with gds. access the GDS.

Also, a node can have any number of labels. So, a Person node can also have the Actor label, or Director, or all 3.

answered May 25, 2023 at 7:53

cybersam

67.3k6 gold badges59 silver badges81 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

How does "gds.graph.project" actually work in Neo4j?

Question

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

Question

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related