在沙发Db或cloudant中查找开始日期和结束日期之间的重叠日期范围

问题描述：

您好，我正在使用数据库作为couchDb构建预订应用程序。我有几个预订文件，每个文件都有roomId，开始日期和结束日期。

Hello I am building a reservation app using database as couchDb. I have several reservation documents and each of them has roomId, start date and end date.

现在，当用户创建带有roomId，开始日期和结束日期的会议请求时，我需要在现有预订中搜索开始时间和结束时间之间的重叠时间范围，仅在没有冲突时创建预订。与此同时，我还需要检查roomid。

Now when user creates a meeting request with roomId, start date and end date, I need to search for overlaps time ranges between the start time and endtime in the existing reservations and create a reservations only when there is no conflict. Along with this I also need to check for roomid.

该要求类似于确定两个日期范围是否重叠。

我已经在沙发上创建了一个视图，并发出了三个键：

I had created a view on my couch db emitting three keys:

function (doc) {  
    if (doc.type == "reservation") {  
         emit([doc.roomid, doc.startTime, doc.endTime], doc);  
    }
}

我确实尝试创建

?startkey=["1970-01-01T00:00:00Z", ""]&endkey=["\ufff0", "1971-01-01T00:00:00Z"]

但是我并没有真正了解如何复合查询

However I am not really getting how to compound query the view to find range of date along with the roomid.

任何帮助将不胜感激。

答

您可以使用 Cloudant查询并指定参考答案中概述的（StartA< = EndB）和（EndA> = StartB）搜索条件。

You could use Cloudant Query and specify the (StartA <= EndB) and (EndA >= StartB) search condition that's outlined in the referenced answer.

创建索引

向 POST 请求c> _index 端点，将以下JSON数据结构作为有效负载传递。

Send a POST request to the _index endpoint, passing the following JSON data structure as payload.

  POST https://$USERNAME:$PASSWORD@$HOST/$DATABASE/_index HTTP/1.1

 {
  "index": {
   "fields": [
     { "name":"startTime",
       "type":"string"
     }, 
     { 
       "name":"endTime",
       "type":"string"
     }, 
     { 
       "name":"roomid",
       "type":"string"
     } 
   ]
  },
  "type": "text"
 }

查询索引

将 POST 请求发送到 _find 端点，将以下JSON数据结构作为有效负载传递。

Send a POST request to the _find endpoint, passing the following JSON data structure as payload.

  POST https://$USERNAME:$PASSWORD@$HOST/$DATABASE/_find HTTP/1.1

  {
   "selector": {
    "startTime": {
      "$lte": "2017-03-06T15:00:00Z"
    },
    "endTime": {
      "$gte": "2017-03-06T14:00:00Z"
    },
    "roomid": {
      "$eq": "room 123"
    }
   }
  }

根据需要替换时间戳和房间标识符值。如果查询返回至少一个文档，则您遇到预订冲突。

Replace the timestamp and room identifier values as needed. If the query returns at least one document you've encountered a booking conflict.

在沙发Db或cloudant中查找开始日期和结束日期之间的重叠日期范围

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