Update relation at runtime - arangodb

Question

I need help in order to update relation at runtime.
I have this use case:
I have created a graph with the following collections:
- A (VertexCollection)
- B (VertexCollection)
- E (EdgeCollection) with relation( A -> B)
at runtme, using Foxx app, I neet to create a new collection (VertexCollection C) and I need to update EdgeCollection with the following relation( A -> [B,C]).
Is there a way to update relation at runtime?
Thanks in advanced,
Peter

Answer 1

You create new collections from Foxx with
var db = require("internal").db;
var C = db._create("C");
An edge collection E can contain edges with in arbitrary vertex collections, you create a new edge in E with:
var edge = E.insert("A/xyz", "C/abc", {"someData":12});
to create an edge from the vertex with _key "xyz" in A to the vertex with _key "abc" in C, say.
Does this answer your question?

Answer 2

In the ArangoDB manual, in section Modify a graph definition during runtime, the following ways for modifying edge definitions at runtime are shown:
Adding a new edge definition to an existing graph:
/* load graph module */
var graph_module = require("org/arangodb/general-graph");
/* load existing graph by name */
var graph = graph_module._graph("myGraph");
/* add a relation for edge collection myEC2, with vertices
between collections myVC1 and myVC3 */
var defs = graph_module._relation("myEC2", ["myVC1"], ["myVC3"]);
/* update the existing graph's definition */
graph._extendEdgeDefinitions(defs);
Modifying an existing edge definition in an existing graph:
/* load graph module */
var graph_module = require("org/arangodb/general-graph");
/* load existing graph by name */
var graph = graph_module._graph("myGraph");
/* update the relation for edge collection myEC2, with vertices
between collections myVC23 and [ myVC42, myVC99 ] */
var defs = graph_module._relation("myEC2", ["myVC23"], ["myVC42", "myVC99"]);
/* update the existing graph's definition */
graph._editEdgeDefinitions(defs);