圖 - 顯示朋友（和第一學位朋友）的朋友

Question

我找到了一個「朋友的朋友」遍歷查詢，它滿足了我朋友朋友的基本需求（friends of friend Query in ArangoDB 3.0）。我已經修改了它稍微使之與文檔中找到「的Knows_Graph」比如工作，我已經添加了一些額外的人（https://docs.arangodb.com/3.1/Manual/Graphs/）

我的查詢使用戴夫爲出發點，並查找他的第二學位朋友通過鮑勃和露西。該腳本工作正常，但我也希望它包括第一學位的朋友（鮑勃和露西）的查詢結果。我可以通過將最小深度設置爲1來完成此操作，但是如果我這樣做，我不會區分Bob和Lucy的深度（請參閱json輸出），所以我無法告訴一個更大的圖，誰是第二度

示例代碼爲2

LET person = DOCUMENT("persons/@persons/dave") 
LET foaf = (
    FOR v IN 2..2 ANY person knows  
    RETURN v 
) 
RETURN MERGE(person, { foaf }) 

分鐘深度的示例使用「知道」邊緣收集和「人」收集

這裏是JSON輸出，如果我有一分鐘深度爲1，最大深度爲2.正如你可以看到bob和lucy與其他人一樣顯示在同一個集合層。我想找到一種方法來以某種方式將它們顯示爲第一級，而不會使查詢過度複雜化或導致性能問題。

[ 
    { 
    "_id": "persons/dave", 
    "_key": "dave", 
    "_rev": "_U7wRsJG--_", 
    "name": "Dave", 
    "foaf": [ 
     { 
     "_key": "lucy", 
     "_id": "persons/lucy", 
     "_rev": "_U8--wPq---", 
     "name": "Lucy" 
     }, 
     { 
     "_key": "henry", 
     "_id": "persons/henry", 
     "_rev": "_U8-_FNa---", 
     "name": "Henry" 
     }, 
     { 
     "_key": "bob", 
     "_id": "persons/bob", 
     "_rev": "_U7wRsJC--_", 
     "name": "Bob" 
     }, 
     { 
     "_key": "charlie", 
     "_id": "persons/charlie", 
     "_rev": "_U7wRsJG---", 
     "name": "Charlie" 
     }, 
     { 
     "_key": "alice", 
     "_id": "persons/alice", 
     "_rev": "_U7wRsJC---", 
     "name": "Alice" 
     }, 
     { 
     "_key": "eve", 
     "_id": "persons/eve", 
     "_rev": "_U7wRsJG--A", 
     "name": "Eve" 
     } 
    ] 
    } 
] 

Answer 1

用下面的查詢你在每個你朋友的深度信息。

LET person = DOCUMENT("persons/@persons/dave") 
LET foaf = (
    FOR v, e, p IN 1..2 ANY person knows  
    RETURN {v, depth: LENGTH(p.edges)} 
) 
RETURN MERGE(person, { foaf }) 

輸出應該是這樣的：

[ 
    { 
    "_id": "persons/dave", 
    "_key": "dave", 
    "_rev": "_U8e0Ube---", 
    "foaf": [ 
     { 
     "v": { 
      "_key": "lucy", 
      "_id": "persons/lucy", 
      "_rev": "_U8e0Y2u---" 
     }, 
     "depth": 1 
     }, 
     { 
     "v": { 
      "_key": "bob", 
      "_id": "persons/bob", 
      "_rev": "_U8ezwCm---" 
     }, 
     "depth": 1 
     }, 
     { 
     "v": { 
      "_key": "charlie", 
      "_id": "persons/charlie", 
      "_rev": "_U8e0-Oe---" 
     }, 
     "depth": 2 
     }, 
     { 
     "v": { 
      "_key": "eve", 
      "_id": "persons/eve", 
      "_rev": "_U8e0loy---" 
     }, 
     "depth": 2 
     }, 
     { 
     "v": { 
      "_key": "alice", 
      "_id": "persons/alice", 
      "_rev": "_U8e0ptu---" 
     }, 
     "depth": 2 
     } 
    ] 
    } 
] 

如果你婉組的每個深度的朋友一起查詢可能看起來像：

LET person = DOCUMENT("persons/@persons/dave") 
LET foaf = (
    FOR v, e, p IN 1..2 ANY person knows  
    COLLECT depth = LENGTH(p.edges) INTO s KEEP v 
    RETURN {depth, foaf: s[*].v} 
) 
RETURN MERGE(person, { foaf }) 

輸出應該是這樣的：

[ 
    { 
    "_id": "persons/dave", 
    "_key": "dave", 
    "_rev": "_U8e0Ube---", 
    "foaf": [ 
     { 
     "depth": 1, 
     "foaf": [ 
      { 
      "_key": "lucy", 
      "_id": "persons/lucy", 
      "_rev": "_U8e0Y2u---" 
      }, 
      { 
      "_key": "bob", 
      "_id": "persons/bob", 
      "_rev": "_U8ezwCm---" 
      } 
     ] 
     }, 
     { 
     "depth": 2, 
     "foaf": [ 
      { 
      "_key": "charlie", 
      "_id": "persons/charlie", 
      "_rev": "_U8e0-Oe---" 
      }, 
      { 
      "_key": "eve", 
      "_id": "persons/eve", 
      "_rev": "_U8e0loy---" 
      }, 
      { 
      "_key": "alice", 
      "_id": "persons/alice", 
      "_rev": "_U8e0ptu---" 
      } 
     ] 
     } 
    ] 
    } 
] 

UPDATE

如果您需要更多關於人與人之間關係的信息，您可以返回路徑而不是頂點。路徑（p）包括所有訪問邊（知道關係）和所有頂點（人）。 有關AQL遍歷語法的更多信息，請參見docs。

LET person = DOCUMENT("persons/@persons/dave") 
LET foaf = (
    FOR v, e, p IN 1..2 ANY person knows  
    COLLECT depth = LENGTH(p.edges) INTO s KEEP p 
    RETURN {depth, foaf: s[*].p} 
) 
RETURN MERGE(person, { foaf })