CouchDB的芒果查詢（CouchDB的2.0.1）

Question

我想查詢以下數據：

（索取：https://dotnetcodr.com/2017/06/21/introduction-to-couchdb-with-net-part-17-starting-with-mango-queries/）

{ 
     "post_code": 35801, 
     "country": "United States", 
     "country_abbreviation": "US", 
     "places": [ 
     { 
      "place_name": "Huntsville", 
      "longitude": -86.5673, 
      "state": "Alabama", 
      "state_abbreviation": "AL", 
      "latitude": 34.7269 
     } 
     ] 
    }, 

    .......... 

我的問題：

1. 如何包括，比如說，首先是查詢中的place_name。

下面的JavaScript並沒有給結果：

{ 
    "selector": { 
     "post_code": {"$eq": 35801} 
    }, 
    "fields":["places.placename"] 
} 

上post_code正確的索引：

{ 
    "index": { 
    "fields": [ 
     "post_code" 
    ] 
    }, 
    "type": "json", 
    "name": "post-code-index" 
} 

我沒有設置其他指標如下：

{ 
    "index": { 
    "fields": [ 
     "places.placename" 
    ] 
    }, 
    "type": "json" 
} 

1. 如果什麼數據有以下字段：

   "old_post_code_numbers": [12345, 67890, ......]

或：

如果數據有以下字段：

"places": 
{ 
    "place_name": "Huntsville", 
    "longitude": -86.5673, 
    "state": "Alabama", 
    "state_abbreviation": "AL", 
    "latitude": 34.7269 
} 

JSON有這麼多的形式，我strug以獲得這些查詢所需的JavaScript背後的原理。 我知道這很簡單。它一定很簡單。

非常感謝我應該/可以訪問任何指導或網站。

編輯：

我設法以下就一個在線的JavaScript測試網站的工作，但我還是沒能得到這個在CouchDB的芒果工作。這當然可以在CouchDB中實現。

var xxx= 
    { 
     "post_code": 82941, 
     "country": "United States", 
     "country_abbreviation": "US", 
     "places": [ 
     { 
      "place_name": "Pinedale", 
      "longitude": -109.8561, 
      "state": "Wyoming", 
      "state_abbreviation": "WY", 
      "latitude": 42.8543 
     }] 
} 

console.log(xxx.places[0].place_name); 

Answer 1

我已經能夠得到的結果對我的問題的一部分1.（基於答案this question），具體如下：

我的指數：

{ 
"type": "json", 
"def": { 
    "fields": [ 
    { 
    "places.0.place_name": "asc" 
    } 
    ] 
} 
} 

我的查詢：

{ 
    "selector": { 
    "places.0.place_name": { 
     "$gte": null 
     } 

    }, 
    "fields": [ 
    "_id", 
    "places.0.place_name" 
    ], 
    "sort": [ 
    { 
     "places.0.place_name": "asc" 
    } 
    ] 
} 

結果：

{"docs":[ 
{"_id":"254b9a8c7a46934363076cc3d9034082","places":{"0":{"place_name":"Aberdeen"}}}, 
{"_id":"254b9a8c7a46934363076cc3d9037559","places":{"0":{"place_name":"Altavista"}}}, 
{"_id":"254b9a8c7a46934363076cc3d900e4d2","places":{"0":{"place_name":"Anchorage"}}}, 
{"_id":"254b9a8c7a46934363076cc3d900f3b9","places":{"0":{"place_name":"Anchorage"}}}, 
{"_id":"254b9a8c7a46934363076cc3d902c738","places":{"0":{"place_name":"Ashland"}}}, 
{"_id":"254b9a8c7a46934363076cc3d901a2f2","places":{"0":{"place_name":"Atlanta"}}}, 
{"_id":"254b9a8c7a46934363076cc3d901a374","places":{"0":{"place_name":"Atlanta"}}} 
................. 

在這種情況下我已經省略了"post_code": {"$eq": 35801}但這可以在沒有錯誤發生的加入。

第3部分：

指數：

{ 
    "index": { 
    "fields": [ 
     { 
     "places.place_name": "asc" 
     } 
    ] 
    }, 
    "type": "json" 
} 

查詢：

{ 
    "selector": { 
    "places.place_name": { 
     "$gte": null 
     } 

    }, 
    "fields": [ 
    "places.place_name" 
    ], 
    "sort": [ 
    { 
     "places.place_name": "asc" 
    } 
    ] 
} 

Result: 

{"docs":[ 
{"places":{"place_name":"Anchorage"}}, 
{"places":{"place_name":"Anchorage"}}, 
{"places":{"place_name":"Huntsville"}}, 
{"places":{"place_name":"Huntsville"}}, 
{"places":{"place_name":"Phoenix"}}, 
{"places":{"place_name":"Phoenix"}} 
]} 

2部分：

指數：

{ 
    "index": { 
    "fields": [ 
     { 
     "old_post_code_numbers": "asc" 
     } 
    ] 
    }, 
    "type": "json" 
} 

查詢：

{ 
    "selector": { 
    "old_post_code_numbers": { 
     "$gte": null 
     } 

    }, 
    "fields": [ 
    "places.place_name", 
    "old_post_code_numbers" 
    ], 
    "sort": [ 
    { 
     "old_post_code_numbers": "asc" 
    } 
    ] 
} 

結果：

{"docs":[ 
{"places":{"place_name":"Huntsville"},"old_post_code_numbers":[12345,67890]}, 
{"places":{"place_name":"Huntsville"},"old_post_code_numbers":[12345,67890]}, 
{"places":{"place_name":"Anchorage"},"old_post_code_numbers":[12345,67890]}, 
{"places":{"place_name":"Anchorage"},"old_post_code_numbers":[12345,67890]}, 
{"places":{"place_name":"Phoenix"},"old_post_code_numbers":[12345,67890]}, 
{"places":{"place_name":"Phoenix"},"old_post_code_numbers":[12345,67890]} 
]} 

使用的最後一個例子："old_post_code_numbers.0"貫穿，給人：

{"docs":[ 
{"places":{"place_name":"Huntsville"},"old_post_code_numbers":{"0":12345}}, 
{"places":{"place_name":"Huntsville"},"old_post_code_numbers":{"0":12345}}, 
{"places":{"place_name":"Anchorage"},"old_post_code_numbers":{"0":12345}}, 
{"places":{"place_name":"Anchorage"},"old_post_code_numbers":{"0":12345}}, 
{"places":{"place_name":"Phoenix"},"old_post_code_numbers":{"0":12345}}, 
{"places":{"place_name":"Phoenix"},"old_post_code_numbers":{"0":12345}} 
]} 

我將不勝感激任何意見。