【Elasticsearch教程7】Mapping字段类型之boolean

一、boolean简介

boolean类型非常简单，它就接受真或假。

二、创建boolean类型的字段

创建一个books索引，name是书名，is_published为是否发行。

PUT books
{
    "mappings":{
        "properties":{
            "name":{
                "type":"keyword"
            },
            "is_published":{
                "type":"boolean"
            }
        }
    }
}
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三、新增数据记录

创建如下7条记录，注意看他们的is_published都不一样。

PUT books/_doc/1
{
  "name": "Java编程思想",
  "is_published": true   	#为真
}

PUT books/_doc/2
{
  "name": "孙哥说Spring5",
  "is_published": "true"  	#为真
}

PUT books/_doc/3
{
  "name": "雷丰阳Spring注解",
  "is_published": false		#为假
}

PUT books/_doc/4
{
  "name": "小码哥Vue.js教程",
  "is_published": "false"	#为假
}

PUT books/_doc/5
{
  "name": "易学教育Flink教程",
  "is_published": ""		#为假
}

PUT books/_doc/6
{
  "name": "尚硅谷Flink教程",
  "is_published": null	 #null字段会被忽略	
}

PUT books/_doc/7
{
  "name": "图灵Java面试指导"  #该文档不存在is_published字段
}

#上面7个都能成功，这一个会插入失败
PUT books/_doc/8
{
  "name": "尚硅谷Java面试指导",
  "is_published": "啥也不是"
}

返回：
"type" : "illegal_argument_exception",
"reason" : "Failed to parse value [啥也不是] as only [true] or [false] are allowed."
}
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四、验证boolean类型查询

4.1 查询is_published=true

GET books/_search
{
  "query": {
    "bool": {
      "filter": [
        {
          "term": {
            "is_published": true
          }
        }
      ]
    }
  }
}
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返回如下：true和"true"是等价的

{
    "hits":[
        {
            "_index":"books",
            "_type":"_doc",
            "_id":"2",
            "_score":0,
            "_source":{
                "name":"孙哥说Spring5",
                "is_published":"true"
            }
        },
        {
            "_index":"books",
            "_type":"_doc",
            "_id":"1",
            "_score":0,
            "_source":{
                "name":"Java编程思想",
                "is_published":true
            }
        }
    ]
}
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4.2 查询is_published=false

GET books/_search
{
  "query": {
    "bool": {
      "filter": [
        {
          "term": {
            "is_published": false
          }
        }
      ]
    }
  }
}
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返回如下：false，"false"和""这3个是等价的

{
    "hits":[
        {
            "_index":"books",
            "_type":"_doc",
            "_id":"4",
            "_score":0,
            "_source":{
                "name":"小码哥Vue.js教程",
                "is_published":"false"
            }
        },
        {
            "_index":"books",
            "_type":"_doc",
            "_id":"3",
            "_score":0,
            "_source":{
                "name":"雷丰阳Spring注解",
                "is_published":false
            }
        },
        {
            "_index":"books",
            "_type":"_doc",
            "_id":"5",
            "_score":0,
            "_source":{
                "name":"易学教育Flink教程",
                "is_published":""
            }
        }
    ]
}
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4.3 对于null和缺失字段

• 总有7条记录，还有2条记录它们不是true也不是false。
• 对is_published字段进行exists查询，可查出这2条记录。
• 在日常开发中一定要注意这些值，否则容易漏处理它们。

GET books/_search
{
  "query": {
    "bool": {
      "must_not": [
        {
          "exists": {
            "field": "is_published"
          }
        }
      ]
    }
  }
}
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返回出在is_published上不存在值的2个文档

{
    "hits":[
        {
            "_index":"books",
            "_type":"_doc",
            "_id":"6",
            "_score":0,
            "_source":{
                "name":"尚硅谷Flink教程",
                "is_published":null
            }
        },
        {
            "_index":"books",
            "_type":"_doc",
            "_id":"7",
            "_score":0,
            "_source":{
                "name":"图灵Java面试指导"
            }
        }
    ]
}
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五、在boolean上进行聚合查询

在boolean上进行terms聚合时，聚合结果中key为0(假)和1(真)，key_as_string为false和true。
按照is_published进行分组聚合：

GET books/_search
{
  "aggs": {
    "publish_state": {
      "terms": {
        "field": "is_published"
      }
    }
  },
  "sort": [ "is_published" ]
}
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返回结果如下：

"buckets" : [
        {
          "key" : 0,
          "key_as_string" : "false",
          "doc_count" : 3
        },
        {
          "key" : 1,
          "key_as_string" : "true",
          "doc_count" : 2
        }
]
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