Elasticsearch不同的过滤器值

Question

我在elasticsearch中有一个大型文档存储,并希望检索不同的过滤器值以便在HTML下拉列表中显示.

一个例子就是这样的

[
    {
        "name": "John Doe",
        "deparments": [
            {
                "name": "Accounts"
            },
            {
                "name": "Management"
            }
        ]
    },
    {
        "name": "Jane Smith",
        "deparments": [
            {
                "name": "IT"
            },
            {
                "name": "Management"
            }
        ]
    }
]

下拉列表应包含一系列部门,即IT,帐户和管理.

有些人请指出我正确的方向从弹性搜索中检索一个独特的部门列表？

谢谢

Answer 1

这是terms聚合(文档)的工作.

你可以拥有这样的不同departments值:

POST company/employee/_search
{
  "size":0,
  "aggs": {
    "by_departments": {
      "terms": {
        "field": "departments.name",
        "size": 0 //see note 1
      }
    }
  }
}

在您的示例中,输出:

{
   ...
   "aggregations": {
      "by_departments": {
         "buckets": [
            {
               "key": "management", //see note 2
               "doc_count": 2
            },
            {
               "key": "accounts",
               "doc_count": 1
            },
            {
               "key": "it",
               "doc_count": 1
            }
         ]
      }
   }
}

另外两个说明:

• 设置size为0会将最大存储桶数设置为Integer.MAX_VALUE.如果有太多departments不同的值,请不要使用它.
• 你可以看到键是terms分析departments值的结果.务必terms在映射为的字段上使用聚合not_analyzed.

例如,使用我们的默认映射(departments.name是一个analyzed字符串),添加此员工:

{
  "name": "Bill Gates",
  "departments": [
    {
      "name": "IT"
    },
    {
      "name": "Human Resource"
    }
  ]
}

会导致这种结果:

{
   ...
   "aggregations": {
      "by_departments": {
         "buckets": [
            {
               "key": "it",
               "doc_count": 2
            },
            {
               "key": "management",
               "doc_count": 2
            },
            {
               "key": "accounts",
               "doc_count": 1
            },
            {
               "key": "human",
               "doc_count": 1
            },
            {
               "key": "resource",
               "doc_count": 1
            }
         ]
      }
   }
}

使用正确的映射:

POST company
{
  "mappings": {
    "employee": {
      "properties": {
        "name": {
          "type": "string"
        },
        "departments": {
          "type": "object",
          "properties": {
            "name": {
              "type": "string",
              "index": "not_analyzed"
            }
          }
        }
      }
    }
  }
}

相同的请求最终输出:

{
   ...
   "aggregations": {
      "by_departments": {
         "buckets": [
            {
               "key": "IT",
               "doc_count": 2
            },
            {
               "key": "Management",
               "doc_count": 2
            },
            {
               "key": "Accounts",
               "doc_count": 1
            },
            {
               "key": "Human Resource",
               "doc_count": 1
            }
         ]
      }
   }
}

希望这可以帮助!