多边缘创建-Gremlin REST服务器

Question

I am using a simple Gremlin RESTful server and I am sending simple commands inside a POST request. For example, if I want to create edges (in my specific format), I have the following template:

const nodeCommandFormat = "graph.addVertex('%s', '%s', 'evid', '%s');" ;

Sending a long string with chained commands like this works fine, all the edges are created. My question is: why it does not work with the edges creation? Until now, I tried with this two commands:

const newEdgeCommandFormat = "gV().has('evid', '%s').addE('next').to(gV().has('evid', '%s')).property('count', 1);" ;

or

x = gV().has('evid', ...).next(); y = gV().has('evid', ...).next(); x.addEdge('next', y, 'count', 1) x = gV().has('evid', ...).next(); y = gV().has('evid', ...).next(); x.addEdge('next', y, 'count', 1) ;

However, if I concatenate 100 commands like this, only the edge corresponding to the last command is created. Why is that? On the other hand, I also receive errors like this:

• Using first type of edge creatio n: [WARN] HttpGremlinEndpointHandler - Invalid request - responding with 500 Internal Server Error and The provided traverser does not map to a value: v[3091]->[TinkerGraphStep(vertex,[evid.eq(6ba0b28797dd79a2ee198d8ff280c4ff)])]
• Using the second type of edge creation : java.util.NoSuchElementException at org.apache.tinkerpop.gremlin.process.traversal.util.DefaultTraversal.next(DefaultTraversal.java:204)

How do I achive dynamic edge creation using Gremlin REST server?

PS All my nodes have "evid" property (event-id) which is the md5 value of an object. I use this as an identifier for my nodes.

Thank you!

Answer 1

.iterate() your traversals. This is highlighted in the Getting Started tutorial right at the end of the "The First 5 Minutes" section.