graph - 如何按传入边数计算和排序

Question

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。

这是我到目前为止所拥有的：

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 
}

我怎样才能用 AQL 做到这一点？

Answer 1

没有索引：以下将返回前 10 名：

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”。限制允许您限制到 TOP 10。请注意，顶点中的类型是“角色”，标签是“ACTS_IN”。

将数字添加到文档并使用排序索引会更有效。但这需要更新文件。

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]