Bidirectional Connections

If a Vertex is loaded, its edges are present in the ActiveOrient::Model-Record.

Lets focus on a sample Vertex

> v  => <V2:0x00000000032c8c58 @metadata={:type=>"d", :class=>"v2", :version=>2, 
                                :fieldTypes=>"in_e2=g", :cluster=>36, :record=>0, 
                                :edges=>{:in=>["e2"], :out=>[]}}, 
         @attributes={:node=>4, :in_e2=>["#52:0"]}> 

ActiveOrientprovides two representations of connected Edges: The :edges Metadata property and the named attribute in_e2. The connected Edge-Classes and even the rid'sif the Edges are present.

Vertex.nodes

After loading the vertex, no information is provided about connected Vertices (Nodes). Vertex.nodes changes that.

Vertex.nodes ( :in -or- :out , via: {Edge-Class -or- Regular-Expression}, where: {a conditon}, expand: {true -or- false} )

After checking the provided via: parameter, Vertex.node delegates the task to OrientQuery.

> v.nodes( :in, via: /e/, expand: true) &.to_human
   INFO->select  expand (  inE('e2').out  ) from #36:0  
  => ["<V1[25:0]: out: {E2=>10}, item : 1>"]

Vertex.nodes can be chained

> pp v.nodes( :in, via: /e/, expand: true).nodes( :out, via: /e2/ , expand: true) &.to_human    
  INFO->select  expand (  inE('e2').out  ) from #36:0  
  INFO->select  expand (  outE('e2').in  ) from #25:0  
[["<V2[33:0]: in: {E2=>1}, node : 1>",
  "<V2[34:0]: in: {E2=>1}, node : 2>",
  "<V2[35:0]: in: {E2=>1}, node : 3>",
  "<V2[36:0]: in: {E2=>1}, node : 4>",
  "<V2[37:0]: in: {E2=>1}, node : 5>",
  "<V2[38:0]: in: {E2=>1}, node : 6>",
  "<V2[39:0]: in: {E2=>1}, node : 7>",
  "<V2[40:0]: in: {E2=>1}, node : 8>",
  "<V2[33:1]: in: {E2=>1}, node : 9>",
  "<V2[34:1]: in: {E2=>1}, node : 10>"]]

and nodes can be filtered

> pp v.nodes( :in, via: /e/, expand: true)
      .nodes( :out, via: /e2/ , expand: true, where:'node>6')
      .map &:to_human 
  INFO->select  expand (  inE('e2').out  ) from #36:0  
  INFO->select  expand (  outE('e2').in[ node>6 ]  ) from #25:0  
[["<V2[39:0]: in: {E2=>1}, node : 7>",
  "<V2[40:0]: in: {E2=>1}, node : 8>",
  "<V2[33:1]: in: {E2=>1}, node : 9>",
  "<V2[34:1]: in: {E2=>1}, node : 10>"]]

Unfortunately, this approach fires one query per traversed layer.

Instead a Regular Expression an Edge-Class can be provided to :via, ie. v.nodes :in, via: E2

note1: Vertex.nodes() returns a ActiveSupport::Array. Any method of V is delegated and thus applied to the collection.

note2 Vertex.match provides an alternative approach to access connected data.

note3 The approach of nodes focuses on outE().in and inE().out

The database offers additional traversal options

• outE: Vertex to outgoing edges
• inE: Vertex to incoming edges
• bothE: Vertex to all edges
• inV: Edge to Vertex (end point)
• outV: Edge to Vertex (starting point)
• bothV: Edge to Vertex (both sizes)
• out: Vertex to Vertex (outgoing edges). Same as outE().inV()
• in: Vertex to Vertex (incoming edges). Same as outE().inV()
• both: Vertex to Vertex (all directions)