Combining Edge and Document Collections in AQL

Question

Is it possible to query, through the same AQL query, several collections effectivelly (with index speed) being some of those edge or document collections? I wanted to emulate more or less the behaviour of foreign keys on RDBMs on tables using edges.

Thanx

Answer 1

I can confirm: EDGES() and NEIGHBORS() will use the automatically available indexes on the _from and/or _to attributes in the edge collections.

You may also join manually using a FILTER clause, e.g.

FOR ...
  FILTER e._from == something_else._id
  RETURN ...

Answer 2

If you are using document fields which are indexed by default then the behaviour is similar to foreign keys in RDBMS. For example, by default, document type collections indexes _id field and edge type collections indexes _id, _from and _to fields. AQL functions such as EDGES or NEIGHBORS are using these indexes to query relevant data.