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Re: similar edges and how to prevent them

yair...@...
 





One Option I thought of that should have worked but doesn't is:

Assuming I have a method to create between 'from' vertex and 'to' vertex:



        Iterator<Edge> edgesIter = from.edges(Direction.OUT, "link");


        while (edgesIter.hasNext()) {
            Edge edge = edgesIter.next();
            Vertex outVertex = edge.outVertex();
            if(outVertex.property("nodeId").value().equals(to.property("nodeId").value())){
                return edge;
            }


        }
        org.apache.tinkerpop.gremlin.structure.Edge linkedEdge = from.addEdge("link", to);
        return linkedEdge;


I still get duplicate edges when I re-run my app. and yes I do commit the tx after i'm done.

Any ideas?


On Monday, September 11, 2017 at 9:53:49 AM UTC+3, ya...@... wrote:

I have an app where I am migration a d non graph DB graph to Janus. So I create the graph when I first start the app. Using cassandra backend.

I have an issue where 2 vertices have "identical" edges (besides the auto-generated id of course) are created in my code causing me to get too many IN and OUT edges.

I read my vertex like this:


javaGraph.traversal().V().hasLabel(instanceId).has("nodeId", lineageNodeId).toList();




I read Both edges:

vertex.edges(org.apache.tinkerpop.gremlin.structure.Direction.IN, "link");


vertex.edges(org.apache.tinkerpop.gremlin.structure.Direction.OUT, "link");


each time I run my app it doesn't "see" the existing edges and adds to it. so I get edges multiplies while I only want "link" edge between any 2 given vertices

in order to make sure I don't create duplicate vertices:


        GraphTraversal<Vertex, Vertex> vertexNode = javaGraph.traversal().V().hasLabel(instanceId).has("nodeId", myNodeId);
        if (vertexNode.hasNext()) {
            return vertexNode.next();
        } else {            

            JanusGraphVertex node = javaGraph.addVertex(instanceId);
            node.property("nodeId", myNodeId);
            return node;
        }



But I don't know once I have vertex A and B at hand - how to verify they are not already connected.






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