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gremlintinkerpop3amazon-neptunegremlinpython

Upsert properties using Gremlin

I'm using python and AWS Neptune.

I'm using the "upsert" pattern by id:

g.V().has(node_type,'id',node.id).fold()
.coalesce(__.unfold(),__.addV('node_type').property('id',node.id)).
property('property','first').next()

Indeed the the vertex is added (Or selected from the graph) with the added property. Now I want to add two more properties which I fail to add:

  1. I want to add "max" property. If the vertex has the property, I want to take the max value of it and the value "10" (for example). Tried to add the following statement to my query but it doesn't work:

    property('time_max', __.max(__.values('max'), 10))

    But I'm getting an exception the "Could not locate method: DefaultGraphTraversal.max"

  2. Another property that Increments "count" property the same way. I got the same exception on the "sack" method.

How can these properties can be added? Is the only way is to get the vertex and then commit it? I want it to be as efficient as possible.

Thanks!

Solution

  • The max() step is used to find the maximum value in a stream or collection such as in this simple example:

    gremlin> g.inject(1,2,3).max()
==>3

    You could do something like this instead

    union(values('max'),constant(10)).max()