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Shortest Path Syntax

When writing a shortest path query, you can either use a named graph or a set of edge collections (anonymous graph).

Syntax for Named Graphs​

Use this syntax if you have created a named graph, which is entered as graphName.

FOR vertex[, edge]
  IN OUTBOUND|INBOUND|ANY SHORTEST_PATH
  startVertex TO targetVertex
  GRAPH graphName
  [OPTIONS options]

Syntax for Collection Sets​

Instead of GRAPH graphName, you can specify a list of edge collections (anonymous graph). The involved vertex collections are determined by the edges of the given edge collections. The rest of the behavior is similar to the named version.

FOR vertex[, edge]
  IN OUTBOUND|INBOUND|ANY SHORTEST_PATH
  startVertex TO targetVertex
  edgeCollection1, ..., edgeCollectionN
  [OPTIONS options]

Syntax Traversing in Mixed Directions​

For a shortest path with a list of edge collections you can optionally specify the direction for some of the edge collections. For example, if you have three edge collections edges1, edges2 and edges3, where in edges2 the direction has no relevance, but in edges1 and edges3 the direction should be taken into account. In this case, you could use OUTBOUND as general search direction and ANY specifically for edges2 as follows:

FOR vertex IN OUTBOUND SHORTEST_PATH
  startVertex TO targetVertex
  edges1, ANY edges2, edges3

All collections in the list that do not specify their own direction will use the direction defined after IN (here: OUTBOUND). This allows you to use a different direction for each collection in your path search.

Query Parameters​

This section explains the parameters of the queries above.

FOR​

Emits up to two variables:

  • vertex (object): The current vertex on the shortest path
  • edge (object, optional): The edge pointing to the vertex

IN OUTBOUND|INBOUND|ANY​

Defines in which direction edges are followed.

  • OUTBOUND: Outgoing
  • INBOUND: Incoming
  • ANY: Both outgoing and incoming

startVertex TO targetVertex​

Both are string objects.

The two vertices between which the shortest path is computed. This can be specified in the form of an ID string or in the form of a document with the attribute _id. All other values will lead to a warning and an empty result. If one of the specified documents does not exist, then the result is empty as well and there is no warning.

GRAPH graphName​

String object. The name identifying the named graph. Its vertex and edge collections are already defined, you do not need to specify them.

OPTIONS options​

Object, optional.

Used to modify the way the traversal runs. Only the following attributes have an effect, all others are ignored:

  • weightAttribute (string): A top-level edge attribute that should be used to read the edge weight. If the attribute is not existent or not numeric, then the defaultWeight is used instead.
  • defaultWeight (number): This value is used as fallback if there is no weightAttribute in the edge document, or if it's not a number. The default is 1.

Conditional shortest path​

The SHORTESTPATH computation will only find an unconditioned shortest path. With this construct it is not possible to define a condition like: "Find the shortest path where all edges are of type _X". If you want to do this, use a normal Traversal instead with the option {bfs: true} in combination with LIMIT 1.

Also consider using WITH to specify the collections you expect to be involved.