如何在有边的 2 个顶点之间插入一个顶点。 Azure Cosmos DB [GREMLIN API]

Question

所以从图中我想保存由user vertex修改的formula vertex的早期版本。

如果公式被修改，这是我想做的事情

• 克隆formula vertex的前一个值，并从最新的formula vertex到前一个formula vertex添加一个previos_value边
• 将modified 边缘从user vertex 添加到前一个formula vertex
• 将所有传出和传入边缘从以前的formula vertex 转移到最新的formula vertex

Answer 1

这将是一个简单的辅助方法来完成这项工作：

modify = { user, product, version ->

  g.V().has("software","name",product).as("s"). /* this would be your formula vertex     */
    valueMap().
      by(unfold()).as("sm").

    addV("software").as("ns").                 /* create a new vertex                    */

    sideEffect(select("sm").unfold().as("kv"). /* copy properties from the old vertex    */
               select("ns").
               property(select("kv").by(keys),
                        select("kv").by(values))).

    property("version",version).               /* set version on the new vertex          */

    select("s").
    sideEffect(                                /* transfer out-edges                     */
      outE().as("e").
      sideEffect(
        select("ns").
        addE(select("e").by(label)).
          to(select("e").inV()).as("ne").
        select("e").properties().as("p").
        select("ne").
          property(select("p").key(),
                   select("p").value())).
      drop()).
    sideEffect(                                /* transfer in-edges                     */
      inE().as("e").
      not(outV().where(eq("s"))).              /* exclude self-referencing edges        */
      sideEffect(
        select("ns").
        addE(select("e").by(label)).
          from(select("e").outV()).as("ne").
        select("e").properties().as("p").
        select("ne").
        property(select("p").key(),
                 select("p").value())).
      drop()).

    select("ns").
    addE("previous_value").to("s").inV().      /* add edges to previous version and user */
    addE("modified").
      from(V().has("person","name",user)).

    iterate()

}

实际上它看起来像这样：

gremlin> g = TinkerFactory.createModern().traversal()
==>graphtraversalsource[tinkergraph[vertices:6 edges:6], standard]
gremlin> 
gremlin> modify = { user, product, version ->
         ...
.....39> }
==>groovysh_evaluate$_run_closure1@7523d5a1
gremlin> 
gremlin> modify("marko","lop","v2")
gremlin> 
gremlin> g.V().has("name","lop").
......1>   inE().outV().
......2>   path().
......3>     by(values("name","version").fold()).
......4>     by(label).
......5>     by(elementMap())
==>[[lop],previous_value,[id:13,label:software,name:lop,lang:java,version:v2]]
==>[[lop],modified,[id:1,label:person,name:marko,age:29]]
==>[[lop,v2],created,[id:1,label:person,name:marko,age:29]]
==>[[lop,v2],created,[id:4,label:person,name:josh,age:32]]
==>[[lop,v2],created,[id:6,label:person,name:peter,age:35]]