弹性搜索查询中间结果 [英] Elasticsearch query with intermediate results

问题描述

我刚刚进入弹性搜索，我有问题查询它有效率。我有以下类型的对象：

• 教师


• Class


• TeacherClass （整数字段 teacher_id 和 class_id ）


• 事件（整数字段 teacher_class_id ）

所以结构看起来像这样：

  ___________ _______________ _________ 
 |老师| _____ / | TeacherClass | \ _____ |类| 
 | _________ | \ | ______________ | / | _______ | 
 | 
 | 
 ___ / _ \ ___ 
 |事件| 
 | _______ | 
  

我想获得与给定老师相关的活动数量。目前我正在做两个查询：

• TeacherClass 获取 TeacherClass ids的数组


• 计数查询事件（计数事件与 teacher_class_id 等于数组中的一个值。

在单个查询中有没有办法？

解决方案

这里的关键是非规范化。您需要对数据进行非规范化，以便每个文档包含以下字段：

  {
teacher_id：1， 
teacher_name：John Math，
class_id：2，
class_name：Math，
event_id：3，
 event_name：我的事件
} 
  

然后，您可以将数据与术语聚合 teacher_id ，并查看使用 value_count sub-aggregation on event_id 。

  {
query：{
match_all：{} 
}，
aggs：{
teachers：{
terms：{
field：teacher_id
}，
aggs：{
events：{
value_count：{
 ：event_id
} 
} 
} 
} 
} 
} 
  

I'm new to elasticsearch and I have problem querying it efficiently. I have following types of objects:

• Teacher
• Class
• TeacherClass (with integer fields teacher_id and class_id)
• Event (with integer field teacher_class_id)

So the structure looks like this:

___________       _______________      _________
| Teacher |_____/| TeacherClass |\_____| Class |
|_________|     \|______________|/     |_______|
                        |
                        |
                    ___/_\___                     
                    | Event |
                    |_______|

I want to get the number of events associated with given teacher. Currently I'm doing this with two queries:

• search query on TeacherClass (to get an array of TeacherClass ids)
• count query on Event (to count events with teacher_class_id equal to one of the values in the array).

Is there a way to do this in a single query?

解决方案

The keyword here is denormalization. You need to denormalize your data so that each document contains the following fields:

{
    "teacher_id": 1,
    "teacher_name": "John Math",
    "class_id": 2,
    "class_name": "Math",
    "event_id": 3,
    "event_name": "My Event"
}

You can then aggregate your data with a terms aggregation on teacher_id and see how many different events you have using a value_count sub-aggregation on event_id.

{
  "query": {
    "match_all": {}
  },
  "aggs": {
    "teachers": {
      "terms": {
        "field": "teacher_id"
      },
      "aggs": {
        "events": {
          "value_count": {
            "field": "event_id"
          }
        }
      }
    }
  }
}

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