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Added documentation for multi-direction collections.

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Michael Hackstein 2016-01-28 16:59:11 +01:00
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Documentation/Books/Users/Aql/GraphTraversals.mdpp
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@ -103,6 +103,17 @@ You have two options here, you can either use a named graph (see [the graphs cha
Instead of the `GRAPH graphName` you may specify a **list of edge collections**. Vertex collections are evaluated from the edges. The rest of the behavior is similar to the named version.
!SUBSUBSECTION Working on collection sets with mixed directions:
For traversals with a **list of edge collections** you can optionally specify the direction for some of the edge collections.
Say for example 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 can use `OUTBOUND` as general traversal direction and `ANY` specifically for `edges2` in the following statement:
`FOR vertex IN OUTBOUND startVertex edges1, ANY edges2, edges3`
All collections in the list that do not specify their own direction will use the direction defined after `IN`.
This allows to use a different direction for each collection in your traversal.
!SUBSECTION Using filters and the explainer to extrapolate the costs
All three variables emitted by the traversals might as well be used in filter statements.