基于nested object实现博客与评论嵌套关系

      创建索引，插入一条数据

PUT /blogs/_doc/1
{
  "title": "花无缺发表的一篇帖子",
  "content": "我是花无缺，大家要不要考虑一下投资房产和买股票的事情啊。。。",
  "tags": [
    "投资",
    "理财"
  ],
  "comments": [
    {
      "name": "小鱼儿",
      "comment": "什么股票啊？推荐一下呗",
      "age": 28,
      "stars": 4,
      "date": "2016-09-01"
    },
    {
      "name": "黄药师",
      "comment": "我喜欢投资房产，风，险大收益也大",
      "age": 31,
      "stars": 5,
      "date": "2016-10-22"
    }
  ]
}

　　查看_mappings

GET /blogs/_mappings

{
  "blogs" : {
    "mappings" : {
      "properties" : {
        "comments" : {
          "properties" : {
            "age" : {
              "type" : "long"
            },
            "comment" : {
              "type" : "text",
              "fields" : {
                "keyword" : {
                  "type" : "keyword",
                  "ignore_above" : 256
                }
              }
            },
            "date" : {
              "type" : "date"
            },
            "name" : {
              "type" : "text",
              "fields" : {
                "keyword" : {
                  "type" : "keyword",
                  "ignore_above" : 256
                }
              }
            },
            "stars" : {
              "type" : "long"
            }
          }
        },
        "content" : {
          "type" : "text",
          "fields" : {
            "keyword" : {
              "type" : "keyword",
              "ignore_above" : 256
            }
          }
        },
        "tags" : {
          "type" : "text",
          "fields" : {
            "keyword" : {
              "type" : "keyword",
              "ignore_above" : 256
            }
          }
        },
        "title" : {
          "type" : "text",
          "fields" : {
            "keyword" : {
              "type" : "keyword",
              "ignore_above" : 256
            }
          }
        },
        "userInfo" : {
          "properties" : {
            "userId" : {
              "type" : "long"
            },
            "username" : {
              "type" : "text",
              "fields" : {
                "keyword" : {
                  "type" : "keyword",
                  "ignore_above" : 256
                }
              }
            }
          }
        }
      }
    }
  }
}

　　需求： 年龄是28岁的黄药师评论过的博客

GET /blogs/_search
{
  "query": {
    "bool": {
      "must": [
        {
          "match": {
            "comments.name": "黄药师"
          }
        },
        {
          "match": {
            "comments.age": 28
          }
        }
      ]
    }
  }
}

　　结果

{
  "took" : 158,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 1,
      "relation" : "eq"
    },
    "max_score" : 1.8630463,
    "hits" : [
      {
        "_index" : "blogs",
        "_type" : "_doc",
        "_id" : "1",
        "_score" : 1.8630463,
        "_source" : {
          "title" : "花无缺发表的一篇帖子",
          "content" : "我是花无缺，大家要不要考虑一下投资房产和买股票的事情啊。。。",
          "tags" : [
            "投资",
            "理财"
          ],
          "comments" : [
            {
              "name" : "小鱼儿",
              "comment" : "什么股票啊？推荐一下呗",
              "age" : 28,
              "stars" : 4,
              "date" : "2016-09-01"
            },
            {
              "name" : "黄药师",
              "comment" : "我喜欢投资房产，风，险大收益也大",
              "age" : 31,
              "stars" : 5,
              "date" : "2016-10-22"
            }
          ]
        }
      }
    ]
  }
}

　　归根到底 还是object类型数据结构的底层存储导致的查询不正确

{
  "title":            [ "花无缺", "发表", "一篇", "帖子" ],
  "content":             [ "我", "是", "花无缺", "大家", "要不要", "考虑", "一下", "投资", "房产", "买", "股票", "事情" ],
  "tags":             [ "投资", "理财" ],
  "comments.name":    [ "小鱼儿", "黄药师" ],
  "comments.comment": [ "什么", "股票", "推荐", "我", "喜欢", "投资", "房产", "风险", "收益", "大" ],
  "comments.age":     [ 28, 31 ],
  "comments.stars":   [ 4, 5 ],
  "comments.date":    [ 2016-09-01, 2016-10-22 ]
}

　　object类型底层数据结构，会将一个json数组中的数据，进行扁平化，所以，直接命中了这个document，name=黄药师，age=28，在范围之内，正好符合，所以被查询出来

解决object查询不对的问题

　 引入nested object类型，来解决object类型底层数据结构导致的问题，修改mapping，将comments的类型从object设置为nested

PUT /blogs
{
  "mappings": {
      "properties": {
        "comments": {
          "type": "nested", 
          "properties": {
            "name":    { "type": "text"  },
            "comment": { "type": "text"  },
            "age":     { "type": "short"   },
            "stars":   { "type": "short"   },
            "date":    { "type": "date"    }
          }
        }
      }
    }
}

　　写数据

PUT /blogs/_doc/1
{
  "title": "花无缺发表的一篇帖子",
  "content":  "我是花无缺，大家要不要考虑一下投资房产和买股票的事情啊。。。",
  "tags":  [ "投资", "理财" ],
  "comments": [ 
    {
      "name":    "小鱼儿",
      "comment": "什么股票啊？推荐一下呗",
      "age":     28,
      "stars":   4,
      "date":    "2016-09-01"
    },
    {
      "name":    "黄药师",
      "comment": "我喜欢投资房产，风，险大收益也大",
      "age":     31,
      "stars":   5,
      "date":    "2016-10-22"
    }
  ]
}

　　nested object 存储如下：

{ 
  "comments.name":    [ "小鱼儿" ],
  "comments.comment": [ "什么", "股票", "推荐" ],
  "comments.age":     [ 28 ],
  "comments.stars":   [ 4 ],
  "comments.date":    [ 2014-09-01 ]
}
{ 
  "comments.name":    [ "黄药师" ],
  "comments.comment": [ "我", "喜欢", "投资", "房产", "风险", "收益", "大" ],
  "comments.age":     [ 31 ],
  "comments.stars":   [ 5 ],
  "comments.date":    [ 2014-10-22 ]
}
{ 
  "title":            [ "花无缺", "发表", "一篇", "帖子" ],
  "body":             [ "我", "是", "花无缺", "大家", "要不要", "考虑", "一下", "投资", "房产", "买", "股票", "事情" ],
  "tags":             [ "投资", "理财" ]
}

　　再次查询

GET /blogs/_search 
{
  "query": {
    "bool": {
      "must": [
        {
          "nested": {
            "path": "comments",
            "query": {
              "bool": {
                "must": [
                  {
                    "match": {
                      "comments.name": "黄药师"
                    }
                  },
                  {
                    "match": {
                      "comments.age": 31
                    }
                  }
                ]
              }
            }
          }
        }
      ]
    }
  }
}

　　有结果