使用OrientDB使用Gremlin进行图遍历和过滤

Question

Group[code=a]->Choice[selected=true]
Group[code=a]->Choice[selected=false]
Group[code=a]->Choice[selected=false]
Group[code=b]->Choice[selected=false]
Group[code=b]->Choice[selected=false]
Group[code=c]->Choice[selected=false]
Group[code=c]->Choice[selected=true]

Given the above Vertices, I'm looking to query for Group Vertices, where a group does not have any Choice vertices, with a selected attribute as true.

Hence the result should return only Group b

Group[code=b]

Any help is appreciated.

Answer 1

Here's your graph - when asking questions about Gremlin it's always helpful to provide your sample data in this way:

graph = TinkerGraph.open()
g = graph.traversal()
g.addV('group').property('code','a').as('a').
  addV('group').property('code','b').as('b').
  addV('group').property('code','c').as('c').
  addV('choice').property('selected',true).
  addE('link').from('a').
  addV('choice').property('selected',false).
  addE('link').from('a').
  addV('choice').property('selected',false).
  addE('link').from('a').
  addV('choice').property('selected',false).
  addE('link').from('b').
  addV('choice').property('selected',false).
  addE('link').from('b').
  addV('choice').property('selected',false).
  addE('link').from('c').
  addV('choice').property('selected',true).
  addE('link').from('c').iterate()

One way to get the answer you want is to do a traversal like this:

gremlin> g.V().hasLabel('group').
......1>   where(__.not(out('link').has('selected',true))).
......2>   values('code')
==>b

The above answer is for TinkerPop 3.x. In TinkerPop 2.x the pattern is the same. You would basically do:

g.V().has('label','group').filter{ it._().out('link').has('selected',true).hasNext() }