changing relation edge

[Tiago Braga Machado]

Hi,

Is it possible changing relation of edges without drop edge? Changing from, to and label for example.

Thanks.

[Stephen Mallette]

No you can't make that change in place like that - the vertices bound to an edge are immutable. With Gremlin, you simply have to drop the edge and add it back (copying in the properties). I suppose you could check the API of the specific graph database you are using to see if it has a way to do that, but I'm not aware of any that do.

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[Daniel Kuppitz]

If you're looking for a single query solution, check this:

Changing the in-vertex of the knows edge between marko and vadas to peter and using a different label for the edge:

gremlin> g = TinkerFactory.createModern().traversal()

==>graphtraversalsource[tinkergraph[vertices:6 edges:6], standard]

gremlin> g.V(1).outE().inV().path().by('name').by(valueMap(true))

==>[marko,[label:created,id:9,weight:0.4],lop]

==>[marko,[label:knows,id:7,weight:0.5],vadas]

==>[marko,[label:knows,id:8,weight:1.0],josh]

 

gremlin> g.V(1).as('a').outE('knows').as('e1').filter(inV().hasId(2)).

           V(6).addE('knows2').from('a').as('e2').

             sideEffect(select('e1').properties().unfold().as('p').

                        select('e2').property(select('p').key(), select('p').value())).

             select('e1').drop()

gremlin> g.V(1).outE().inV().path().by('name').by(valueMap(true))

==>[marko,[label:knows2,id:13,weight:0.5],peter]

==>[marko,[label:created,id:9,weight:0.4],lop]

==>[marko,[label:knows,id:8,weight:1.0],josh]

Cheers,

Daniel