Recursive Queries

[ashwin95r (Ashwin)]

@mandolyte

While you’d want to avoid visiting the same node twice to avoid infinite loops, you also need a way to detect such loops. So perhaps an option to flag such a node.

This can be returned as a list separately. Would that work? We can have a option saying, flagdup which can return these nodes if requested. Let me know what you think.[quote=“mandolyte, post:7, topic:1306”]
Since an edge type could easily have multiple node types on the to-side (object-side?), then you’d want a filter to restrict the traversal to just the node types desired.
[/quote]

You can use different types of filters to achieve this effect I think. Please have a look at: https://wiki.dgraph.io/Query_Language#Functions
https://wiki.dgraph.io/Query_Language#Facets_:_Edge_attributes

@mandolyte

Once the traversal is done, the results need a “projection” so that the results have the attributes from nodes/edges in the returned result

This projection is part of the recursion. In dgraph the values are also stored as nodes. So, for example you want the flight number, you’d specify the corresponding predicate within the recurse query.

{
 recurse(id: <flight-id>) {
  destination
  connecting-flight
  name  # value
  flight-number  # value
 }
}