graph-databases - 如何“连接”顶点及其边数作为 JanusGraph 或 Gremlin 中这些顶点的“属性”？

Question

我需要返回“帖子”顶点，但是这些帖子有一些“喜欢”的边缘，我怎样才能返回该帖子的“喜欢”边缘的计数作为该边缘的属性，如下所示：

{标题：'lorem ipsum.....'，内容：'yadayadayada'， 喜欢：6 <----}

Answer 1

以 TinkerPop 的现代玩具图为例，您可以执行以下操作：

gremlin> g.V().as('a').
......1>   map(outE('created').count()).as('count').
......2>   select('a','count').by(valueMap()).by()
==>[a:[name:[marko],age:[29]],count:1]
==>[a:[name:[vadas],age:[27]],count:0]
==>[a:[name:[lop],lang:[java]],count:0]
==>[a:[name:[josh],age:[32]],count:2]
==>[a:[name:[ripple],lang:[java]],count:0]
==>[a:[name:[peter],age:[35]],count:1]

它返回“a”中顶点的属性和“已创建”边的计数。您也可以选择使用project()：

gremlin> g.V().
......1>   project('a','knows','created').
......2>     by(valueMap()).
......3>     by(outE('knows').count()).
......4>     by(outE('created').count())
==>[a:[name:[marko],age:[29]],knows:2,created:1]
==>[a:[name:[vadas],age:[27]],knows:0,created:0]
==>[a:[name:[lop],lang:[java]],knows:0,created:0]
==>[a:[name:[josh],age:[32]],knows:0,created:2]
==>[a:[name:[ripple],lang:[java]],knows:0,created:0]
==>[a:[name:[peter],age:[35]],knows:0,created:1]