has_parent 查询如何与 Elasticsearch 中的连接数据类型一起使用？答案

【问题标题】：How does a has_parent query work with the join datatype in Elasticsearch?has_parent 查询如何与 Elasticsearch 中的连接数据类型一起使用？
【发布时间】：2019-07-26 03:16:31
【问题描述】：

在查询使用join 数据类型设置的索引时，我无法让has_parent 查询返回任何结果。我完全按照Elasticsearch's join datatype documentation page 上的示例进行操作：

添加一个索引，其中包含question（父）和answer（子）之间的连接：

PUT my_index
{
  "settings": {
    "mapping.single_type": true
  },
  "mappings": {
    "doc": {
      "properties": {
        "my_join_field": { 
          "type": "join",
          "relations": {
            "question": "answer" 
          }
        }
      }
    }
  }
}

添加两个问题：

PUT my_index/doc/1?refresh
{
  "text": "This is a question",
  "my_join_field": {
    "name": "question" 
  }
}

PUT my_index/doc/2?refresh
{
  "text": "This is a another question",
  "my_join_field": {
    "name": "question"
  }
}

添加两个答案：

PUT my_index/doc/3?routing=1&refresh 
{
  "text": "This is an answer",
  "my_join_field": {
    "name": "answer", 
    "parent": "1" 
  }
}

PUT my_index/doc/4?routing=1&refresh
{
  "text": "This is another answer",
  "my_join_field": {
    "name": "answer",
    "parent": "1"
  }
}

该文档没有示例说明如何使用has_parent 查询来查询。这是我的尝试，基于the has_parent doc，但它没有返回任何结果：

GET my_index/_search
{
  "query": {
    "has_parent": { 
      "parent_type": "question",
      "query" : {
        "match" : { "text" : "another" }
      }
    }
  }
}

即使这会返回一个问题和一个答案，正如预期的那样：

GET my_index/_search
{
  "query": {
    "match" : { "text" : "another" }
  }
}

我使用的是 Elasticsearch 5.6.2。

【问题讨论】：

标签： elasticsearch elasticsearch-5

【解决方案1】：

这就是 has_parent 和 has_child 查询如何使用新的连接数据类型。为了回答您的问题，我使用了相同的数据作为索引。从您的示例来看，您似乎希望使用 has_child 查询。

PUT my_index
{
  "settings": {
    "mapping.single_type": true
  },
  "mappings": {
    "doc": {
      "properties": {
        "my_join_field": {
          "type": "join",
          "relations": {
            "question": "answer"
          }
        }
      }
    }
  }
}

PUT my_index/doc/1?refresh
{
  "text": "This is a question",
  "my_join_field": {
    "name": "question" 
  }
}

PUT my_index/doc/2?refresh
{
  "text": "This is a another question",
  "my_join_field": {
    "name": "question"
  }
}

PUT my_index/doc/3?routing=1&refresh 
{
  "text": "This is an answer",
  "my_join_field": {
    "name": "answer", 
    "parent": "1" 
  }
}

PUT my_index/doc/4?routing=1&refresh
{
  "text": "This is another answer",
  "my_join_field": {
    "name": "answer",
    "parent": "1"
  }
}

# has_parent query 
# added inner_hits to see what matched
GET my_index/_search
{
  "query": {
    "has_parent": {
      "parent_type": "question",
      "query": {
        "match": {
          "text": "This is a question"
        }
      },
      "inner_hits": {}
    }
  }
}

# has_child query
GET my_index/_search
{
  "query": {
    "has_child": {
      "type": "answer",
      "query": {
        "match": {
          "text": "another"
        }
      }
    }
  }
}

【讨论】：