结构化搜索

一、结构化数据

1.1 结构化搜索（Structured search）是指对结构化数据的搜索

• 日期，布尔类型和数字都是结构化的

1.2 文本也可以是结构化的

• 如彩色笔可以有离散的颜色集合：红（red） 绿（green） 蓝（blue）
• 一个博客可能被标记为标签，例如，分布式（distributed）和搜索（search）
• 电商网站上的商品都有UPCS（通用商品码Universal Product Codes）或其他的唯一标识，他们都需要遵从严格规定的、结构化的格式

二、ES中的结构化搜索

2.1 布尔，时间，日期和数字这类结构化数据：有精确的格式，我们可以对这些格式进行逻辑操作。

• 包括比较数字或时间的范围，或判定两个值的大小

2.2 结构化的文本可以做精确匹配或者部分匹配

• Term 查询 / Prefix 前缀查询

2.3 结构化的结果只有“是”或“否”两个值

• 根据场景需要，可以决定结构化搜索是否需要打分

三、布尔值

image.png

对布尔值，通过constant score 转成 filtering，没有算分

image.png

四、数字

• 数字类型 Term 单个值

POST products/_search
{
  "profile": "true",
  "explain": true,
  "query": {
    "term": {
      "price": 30
    }
  }
}

• 数字类型 Terms 多个值 类比 SQL中的in函数

POST products/_search
{
  "query": {
    "constant_score": {
      "filter": {
        "terms": {
          "price": [
            "20",
            "30"
          ]
        }
      }
    }
  }
}

• 数字范围 20 <= price <= 30

  
  
  image.png

五、日期 Range 范围

image.png

六、处理空值 exists

image.png

七、查询多个精确值 terms

image.png

• 匹配一个精确值

#数字类型 terms
POST products/_search
{
  "query": {
    "constant_score": {
      "filter": {
        "terms": {
          "price": [
            "20"
          ]
        }
      }
    }
  }
}

八、Term查询是包含，不是完全相等。针对多字段查询要尤其注意

image.png

#结构化搜索，精确匹配
DELETE products
POST /products/_bulk
{ "index": { "_id": 1 }}
{ "price" : 10,"avaliable":true,"date":"2018-01-01", "productID" : "XHDK-A-1293-#fJ3" }
{ "index": { "_id": 2 }}
{ "price" : 20,"avaliable":true,"date":"2019-01-01", "productID" : "KDKE-B-9947-#kL5" }
{ "index": { "_id": 3 }}
{ "price" : 30,"avaliable":true, "productID" : "JODL-X-1937-#pV7" }
{ "index": { "_id": 4 }}
{ "price" : 30,"avaliable":false, "productID" : "QQPX-R-3956-#aD8" }

GET products/_mapping



#对布尔值 match 查询，有算分
POST products/_search
{
  "profile": "true",
  "explain": true,
  "query": {
    "term": {
      "avaliable": true
    }
  }
}



#对布尔值，通过constant score 转成 filtering，没有算分
POST products/_search
{
  "profile": "true",
  "explain": true,
  "query": {
    "constant_score": {
      "filter": {
        "term": {
          "avaliable": true
        }
      }
    }
  }
}


#数字类型 Term
POST products/_search
{
  "profile": "true",
  "explain": true,
  "query": {
    "term": {
      "price": 30
    }
  }
}

#数字类型 terms
POST products/_search
{
  "query": {
    "constant_score": {
      "filter": {
        "terms": {
          "price": [
            "20",
            "30"
          ]
        }
      }
    }
  }
}

#数字 Range 查询
GET products/_search
{
    "query" : {
        "constant_score" : {
            "filter" : {
                "range" : {
                    "price" : {
                        "gte" : 20,
                        "lte"  : 30
                    }
                }
            }
        }
    }
}


# 日期 range
POST products/_search
{
    "query" : {
        "constant_score" : {
            "filter" : {
                "range" : {
                    "date" : {
                      "gte" : "now-1y"
                    }
                }
            }
        }
    }
}



#exists查询
POST products/_search
{
  "query": {
    "constant_score": {
      "filter": {
        "exists": {
          "field": "date"
        }
      }
    }
  }
}

#处理多值字段
POST /movies/_bulk
{ "index": { "_id": 1 }}
{ "title" : "Father of the Bridge Part II","year":1995, "genre":"Comedy"}
{ "index": { "_id": 2 }}
{ "title" : "Dave","year":1993,"genre":["Comedy","Romance"] }


#处理多值字段，term 查询是包含，而不是等于
POST movies/_search
{
  "query": {
    "constant_score": {
      "filter": {
        "term": {
          "genre.keyword": "Comedy"
        }
      }
    }
  }
}


#字符类型 terms
POST products/_search
{
  "query": {
    "constant_score": {
      "filter": {
        "terms": {
          "productID.keyword": [
            "QQPX-R-3956-#aD8",
            "JODL-X-1937-#pV7"
          ]
        }
      }
    }
  }
}



POST products/_search
{
  "profile": "true",
  "explain": true,
  "query": {
    "match": {
      "price": 30
    }
  }
}


POST products/_search
{
  "profile": "true",
  "explain": true,
  "query": {
    "term": {
      "date": "2019-01-01"
    }
  }
}

POST products/_search
{
  "profile": "true",
  "explain": true,
  "query": {
    "match": {
      "date": "2019-01-01"
    }
  }
}




POST products/_search
{
  "profile": "true",
  "explain": true,
  "query": {
    "constant_score": {
      "filter": {
        "term": {
          "productID.keyword": "XHDK-A-1293-#fJ3"
        }
      }
    }
  }
}

POST products/_search
{
  "profile": "true",
  "explain": true,
  "query": {
    "term": {
      "productID.keyword": "XHDK-A-1293-#fJ3"
    }
  }
}

#对布尔数值
POST products/_search
{
  "query": {
    "constant_score": {
      "filter": {
        "term": {
          "avaliable": "false"
        }
      }
    }
  }
}

POST products/_search
{
  "query": {
    "term": {
      "avaliable": {
        "value": "false"
      }
    }
  }
}

POST products/_search
{
  "profile": "true",
  "explain": true,
  "query": {
    "term": {
      "price": {
        "value": "20"
      }
    }
  }
}

POST products/_search
{
  "profile": "true",
  "explain": true,
  "query": {
    "match": {
      "price": "20"
    }
    }
  }
}


POST products/_search
{
  "query": {
    "constant_score": {
      "filter": {
        "bool": {
          "must_not": {
            "exists": {
              "field": "date"
            }
          }
        }
      }
    }
  }
}

https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-exists-query.html https://www.elastic.co/guide/en/elasticsearch/reference/7.1/term-level-queries.html