How I can get tree ?

[jayaemekar]

I checked the code and didn`t find implementation of Tree Step.

Let`s say we have Employee Vertex and a Manages Edge ..,
If i want to get all the tree of one Manager with TreeStep would be something like ...

what I need is vertexes with "parent Id" or use the ".tree()" step
g.V('empid','pk').hasLabel('empVertex').repeat(out('ChildMemberEdge').hasLabel('empvertex')).emit().tree()
but I don't find how to do that with gremlinQ

The return type I guess should be ValueTask<(EmployeeVertex, IEnumerable)[]>

[danielcweber]

From the provided required result type (ValueTask<(EmployeeVertex, IEnumerable)[]>) it appears you don't require a whole deserialization of a tree structure, but rather a collection of all reachable vertices from a root vertex. If that's the case, a projection is probably what you want:

g
  .V('empid','pk')
  .hasLabel('empVertex')
  .project('root', 'nodes')
  .by(identity())
  .by(__
    .repeat(out('ChildMemberEdge').hasLabel('empvertex'))
    .emit()
    .fold())

Is my assumption correct? If not, there's unfortunately no tree step support in Gremlinq.

[jayaemekar]

Thanks for response. How I can have this query using ExRam.Gremlinq.Providers.CosmosDb, Some functions from below one are not available

g
.V('empid','pk')
.hasLabel('empVertex')
.project('root', 'nodes')
.by(identity())
.by(__
.repeat(out('ChildMemberEdge').hasLabel('empvertex'))
.emit()
.fold())

[danielcweber]

What exactly is missing ?

[jayaemekar]

When I tried to convert the query in the format,

g .V(uniqueId) .OfType<EmpVertex>() .Project(p => p.ToDynamic()) .Identity() .Loop(__ => __.Emit().Repeat(__ => __.OutE().InV())) .Emit() .Fold();

Not sure how I can use By Identity and Project function in this query which give me the result of root and childnodes

[anheri]

cosmos db does not support the emit() step

[anheri]

I would like to see the tree() feature in gremlinq aswell as cosmos db, do support the tree step

[danielcweber]

@jayaemekar Have a look at e.g. this unit test to get an idea of how to use Project...By... correctly.

[tomiasp]

Hi, this project() by() out() fold() pattern is 10x more expensive for same result as tree() operation would be. With cosmos, we are using this mentioned pattern, and for example an query to find managers for employees costs 375 RU's. Similar query with tree() operation costs 40 RUs...

[tomiasp]

@jayaemekar btw, you can now find the Tree() -operator in the newest release.