Tinkerpop表达式

Question

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在上图中，我有users、Clients、Sites和Jobs。用户连接到客户端(管理)和客户端(有) -->站点(有)->作业。我正在尝试获得所有拥有活跃工作的客户。

g.V().hasLabel('user').
      has('id', '338d219c-3457-4ad8-8172-37a7d897c0df').
      outE('manages').
      inV().
      hasLabel('client').
      outE('have').
      inV().
      hasLabel('site').
      outE('have').
      inV().
      hasLabel('job').
      has('status', 'In Progress')

上面的查询获取所有作业，但我对了解客户端、站点和作业感兴趣。我想知道我怎样才能做到这一点？

Answer 1

有几种方法可以做到这一点，但首先让我们简化现有的Gremlin，因为您说它可以做您想做的事情：

g.V().has('user','id','338d219c-3457-4ad8-8172-37a7d897c0df').
  out('manages').
  hasLabel('client').
  out('have').
  hasLabel('site').
  out('have').
  has('job','status', 'In Progress')

请注意，像这样的outE().inV()组合本质上就是out()。事实上，如果你把它们写成outE().inV()，那么当应用策略时，Gremlin将经历重写遍历到out()的麻烦。请参阅以下两次遍历的explain()：

gremlin> g.V().outE().inV().outE().inV().explain()
==>Traversal Explanation
=============================================================================================================================================================
Original Traversal                 [GraphStep(vertex,[]), VertexStep(OUT,edge), EdgeVertexStep(IN), VertexStep(OUT,edge), EdgeVertexStep(IN)]

ConnectiveStrategy           [D]   [GraphStep(vertex,[]), VertexStep(OUT,edge), EdgeVertexStep(IN), VertexStep(OUT,edge), EdgeVertexStep(IN)]
MatchPredicateStrategy       [O]   [GraphStep(vertex,[]), VertexStep(OUT,edge), EdgeVertexStep(IN), VertexStep(OUT,edge), EdgeVertexStep(IN)]
FilterRankingStrategy        [O]   [GraphStep(vertex,[]), VertexStep(OUT,edge), EdgeVertexStep(IN), VertexStep(OUT,edge), EdgeVertexStep(IN)]
InlineFilterStrategy         [O]   [GraphStep(vertex,[]), VertexStep(OUT,edge), EdgeVertexStep(IN), VertexStep(OUT,edge), EdgeVertexStep(IN)]
IncidentToAdjacentStrategy   [O]   [GraphStep(vertex,[]), VertexStep(OUT,vertex), VertexStep(OUT,vertex)]
AdjacentToIncidentStrategy   [O]   [GraphStep(vertex,[]), VertexStep(OUT,vertex), VertexStep(OUT,vertex)]
RangeByIsCountStrategy       [O]   [GraphStep(vertex,[]), VertexStep(OUT,vertex), VertexStep(OUT,vertex)]
RepeatUnrollStrategy         [O]   [GraphStep(vertex,[]), VertexStep(OUT,vertex), VertexStep(OUT,vertex)]
PathRetractionStrategy       [O]   [GraphStep(vertex,[]), VertexStep(OUT,vertex), VertexStep(OUT,vertex)]
LazyBarrierStrategy          [O]   [GraphStep(vertex,[]), VertexStep(OUT,vertex), NoOpBarrierStep(2500), VertexStep(OUT,vertex), NoOpBarrierStep(2500)]
TinkerGraphCountStrategy     [P]   [GraphStep(vertex,[]), VertexStep(OUT,vertex), NoOpBarrierStep(2500), VertexStep(OUT,vertex), NoOpBarrierStep(2500)]
TinkerGraphStepStrategy      [P]   [TinkerGraphStep(vertex,[]), VertexStep(OUT,vertex), NoOpBarrierStep(2500), VertexStep(OUT,vertex), NoOpBarrierStep(2500)]
ProfileStrategy              [F]   [TinkerGraphStep(vertex,[]), VertexStep(OUT,vertex), NoOpBarrierStep(2500), VertexStep(OUT,vertex), NoOpBarrierStep(2500)]
StandardVerificationStrategy [V]   [TinkerGraphStep(vertex,[]), VertexStep(OUT,vertex), NoOpBarrierStep(2500), VertexStep(OUT,vertex), NoOpBarrierStep(2500)]

Final Traversal                    [TinkerGraphStep(vertex,[]), VertexStep(OUT,vertex), NoOpBarrierStep(2500), VertexStep(OUT,vertex), NoOpBarrierStep(2500)]
gremlin> g.V().out().out().explain()
==>Traversal Explanation
=============================================================================================================================================================
Original Traversal                 [GraphStep(vertex,[]), VertexStep(OUT,vertex), VertexStep(OUT,vertex)]

ConnectiveStrategy           [D]   [GraphStep(vertex,[]), VertexStep(OUT,vertex), VertexStep(OUT,vertex)]
MatchPredicateStrategy       [O]   [GraphStep(vertex,[]), VertexStep(OUT,vertex), VertexStep(OUT,vertex)]
FilterRankingStrategy        [O]   [GraphStep(vertex,[]), VertexStep(OUT,vertex), VertexStep(OUT,vertex)]
InlineFilterStrategy         [O]   [GraphStep(vertex,[]), VertexStep(OUT,vertex), VertexStep(OUT,vertex)]
IncidentToAdjacentStrategy   [O]   [GraphStep(vertex,[]), VertexStep(OUT,vertex), VertexStep(OUT,vertex)]
AdjacentToIncidentStrategy   [O]   [GraphStep(vertex,[]), VertexStep(OUT,vertex), VertexStep(OUT,vertex)]
RangeByIsCountStrategy       [O]   [GraphStep(vertex,[]), VertexStep(OUT,vertex), VertexStep(OUT,vertex)]
RepeatUnrollStrategy         [O]   [GraphStep(vertex,[]), VertexStep(OUT,vertex), VertexStep(OUT,vertex)]
PathRetractionStrategy       [O]   [GraphStep(vertex,[]), VertexStep(OUT,vertex), VertexStep(OUT,vertex)]
LazyBarrierStrategy          [O]   [GraphStep(vertex,[]), VertexStep(OUT,vertex), NoOpBarrierStep(2500), VertexStep(OUT,vertex), NoOpBarrierStep(2500)]
TinkerGraphCountStrategy     [P]   [GraphStep(vertex,[]), VertexStep(OUT,vertex), NoOpBarrierStep(2500), VertexStep(OUT,vertex), NoOpBarrierStep(2500)]
TinkerGraphStepStrategy      [P]   [TinkerGraphStep(vertex,[]), VertexStep(OUT,vertex), NoOpBarrierStep(2500), VertexStep(OUT,vertex), NoOpBarrierStep(2500)]
ProfileStrategy              [F]   [TinkerGraphStep(vertex,[]), VertexStep(OUT,vertex), NoOpBarrierStep(2500), VertexStep(OUT,vertex), NoOpBarrierStep(2500)]
StandardVerificationStrategy [V]   [TinkerGraphStep(vertex,[]), VertexStep(OUT,vertex), NoOpBarrierStep(2500), VertexStep(OUT,vertex), NoOpBarrierStep(2500)]

Final Traversal                    [TinkerGraphStep(vertex,[]), VertexStep(OUT,vertex), NoOpBarrierStep(2500), VertexStep(OUT,vertex), NoOpBarrierStep(2500)]

看到最后几行是如何相同的了吗？IncidentToAdjacentStrategy会应用该更改，因此最终两次遍历都会编译成相同的内容。

在回答您最初的问题时，如果需要客户端、站点和作业，则使用select()

g.V().has('user','id','338d219c-3457-4ad8-8172-37a7d897c0df').
  out('manages').
  hasLabel('client').as('c').
  out('have').
  hasLabel('site').as('s').
  out('have').
  has('job','status', 'In Progress').as('j').
  select('c','s','j')