如何按传入边的数量计数和排序 [英] How to count and order by number of incoming edges

问题描述

我正在尝试获取出演电影最多的十个人，并按降序获取电影的名称和数量.我正在使用 IMDB 数据集.

I am trying to get get the ten people who have starred in the most movies and get the name and the number of movies in decending order. I am using the IMDB dataset.

这是我目前所拥有的:

arangosh [_system]>   var Graph = require("org/arangodb/graph").Graph;
arangosh [_system]>   var db = require("org/arangodb").db;
arangosh [_system]> statement = db._createStatement({query: 'FOR vert IN imdb_vertices FILTER vert.type == "Person" LET edge_count = (LENGTH(EDGES(imdb_edges, vert, "outbound", [{type: "ACTS_IN"}]))) RETURN {"name": vert.name,  "count": edge_count}'})
[object ArangoStatement]

arangosh [_system]> cursor = statement.execute()
[object ArangoQueryCursor]

arangosh [_system]> cursor.next()
{ 
  "name" : "Stephanie Faracy", 
  "count" : 0 
}

如何使用 AQL 做到这一点?

How can I do that with AQL?

推荐答案

没有索引:以下将返回 Top-10:

Without an index: The following will return the Top-10:

arangosh [_system]> db._createStatement({query: 'FOR vert IN imdb_vertices FILTER vert.type == "Person" LET edge_count = (LENGTH(EDGES(imdb_edges, vert, "outbound", [{"type": "Role", "$label": "ACTS_IN"}]))) SORT edge_count DESC LIMIT 10 RETURN {"name": vert.name,  "count": edge_count}'}).execute().toArray()
[ 
  { 
    "name" : "Clint Eastwood", 
    "count" : 148 
  }, 
  { 
    "name" : "Claude Jade", 
    "count" : 142 
  }, 
  { 
    "name" : "Samuel L. Jackson", 
    "count" : 122 
  }, 
  { 
    "name" : "Armin Mueller-Stahl", 
    "count" : 112 
  }, 
  { 
    "name" : "Gérard Depardieu", 
    "count" : 104 
  }, 
  { 
    "name" : "Marisa Mell", 
    "count" : 104 
  }, 
  { 
    "name" : "Robert De Niro", 
    "count" : 104 
  }, 
  { 
    "name" : "Bruce Willis", 
    "count" : 96 
  }, 
  { 
    "name" : "Jackie Chan", 
    "count" : 94 
  }, 
  { 
    "name" : "Michael Caine", 
    "count" : 90 
  } 
]

基本上，您也可以对使用 LET 创建的变量使用排序".Limit 允许你限制在 TOP 10.注意顶点的类型是'Role'，标签是'ACTS_IN'.

Basically you can use the "sort" also for variables created with LET. Limit allows you to restrict to the TOP 10. Note that the type in vertex is 'Role' and label is 'ACTS_IN'.

将数字添加到文档并使用排序索引会更有效.但这需要更新文档.

It would be more efficient to add the number to the documents and use a sorted index. But this would require to updating the documents.

arangosh [_system]> c = db._createStatement({query: 'FOR vert IN imdb_vertices FILTER vert.type == "Person" LET edge_count = (LENGTH(EDGES(imdb_edges, vert, "outbound", [{"type": "Role", "$label": "ACTS_IN"}]))) RETURN {"_key": vert._key,  "count": edge_count}'}).execute()
[object ArangoQueryCursor]

arangosh [_system]> while (c.hasNext()) { var d = c.next(); db.imdb_vertices.update(d._key, {COUNT: d.count}); }

arangosh [_system]> db.imdb_vertices.ensureSkiplist("COUNT");

arangosh [_system]> x = db._createStatement({query: 'FOR vert in imdb_vertices FILTER vert.COUNT >= 0 SORT vert.COUNT DESC LIMIT 10 RETURN vert'}).execute()
[object ArangoQueryCursor]

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