[SOLVED] Gremlin Value Map With Array of Edges

Gremlin Value Map With Array of Edges

I am trying to query a vertex with Node Gremlin and AWS Neptune for its properties and get all vertices connected to it by an 'out' edge and all of their properties as well in a single output. For instance, if I have a 'Baker' vertex with an edge 'bakes' to two 'Cake' vertices, I want to get a 'Baker' object with all his properties as well as an array on him of the two 'Cake' vertices as objects with all their properties.

I know I can effectively do this with a .project but I do not want to have to select for specific properties for any vertices because I want all of their properties.

I am currently working with a query like this: g.V(BakerId).as('Baker').out('bakes').as('Cake').select('Baker','Cake').by(valueMap(true)), but the problem with this is that this query gives me a list of two outputs, one with the Baker and the first Cake and another with the same Baker and the second cake. I want to avoid the redundancy and have it consolidated in a single output with the Baker appearing just once.

I also am hoping for a solution versatile enough (or simple enough to easily extend) to handle going yet a level deeper to do the same with 'out' edges on the 'Cake' vertices e.g. 'Cake' --> 'madeOf' --> 'Ingredient' so I can get a single Baker with each Cake on it just once each with each Ingredient on them just once each, and all with all their properties as well.

Solution

You can use two project steps and use valueMap so you won't need to sespecifiy the properties:

g.V().hasLabel('Baker').
  project('Baker', 'Cake').
    by(valueMap(true)).
    by(out('bakes').
      project('Cake', 'Ingredients').
        by(valueMap(true)).
        by(out('madeOf').valueMap(true).
          fold()).fold())

example: https://gremlify.com/34e9o3r9gag