使用gremlin添加边缘(如果不存在) [英] Add edge if not exist using gremlin

问题描述

我正在使用天蓝色的宇宙图数据库.

I'm using cosmos graph db in azure.

有人知道只有在不存在两个顶点之间才可以添加边的方法吗(使用gremlin图查询)?

Does anyone know if there is a way to add an edge between two vertex only if it doesn't exist (using gremlin graph query)?

添加顶点时可以做到这一点，但不能添加边.我从这里:

I can do that when adding a vertex, but not with edges. I took the code to do so from here:

g.Inject(0).coalesce(__.V().has('id', 'idOne'), addV('User').property('id', 'idOne'))

谢谢！

推荐答案

可以对边缘进行处理.模式在概念上与顶点相同，并以coalesce()为中心.使用现代" TinkerPop玩具图来演示:

It is possible to do with edges. The pattern is conceptually the same as vertices and centers around coalesce(). Using the "modern" TinkerPop toy graph to demonstrate:

gremlin> g.V().has('person','name','vadas').as('v').
           V().has('software','name','ripple').
           coalesce(__.inE('created').where(outV().as('v')),
                    addE('created').from('v').property('weight',0.5))
==>e[13][2-created->5]

在这里，我们在"vadas"和"ripple"之间添加一条边，但前提是该边不存在.这里的关键是检查coalesce()的第一个参数.

Here we add an edge between "vadas" and "ripple" but only if it doesn't exist already. the key here is the check in the first argument to coalesce().

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