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es使用与原理1 -- 简单啊的API及filter与query

es使用与原理1 -- 简单啊的API及filter与query

作者: Teemo_fca4 | 来源:发表于2020-03-20 15:52 被阅读0次
复杂类型数据及Object类型数据

1、multivalue field
建立索引时与string是一样的,数据类型不能混tag1 tag2 要么全是数字 要么全是字符串

{ "tags": [ "tag1", "tag2" ]}

2、empty field

null,[],[null]

3、object field

PUT /company/employee/1
{
  "address": {
    "country": "china",
    "province": "guangdong",
    "city": "guangzhou"
  },
  "name": "jack",
  "age": 27,
  "join_date": "2017-01-01"
}

上面的address就是 object类型,address Object 数据底层的存储

{
    "name":            [jack],
    "age":          [27],
    "join_date":      [2017-01-01],
    "address.country":         [china],
    "address.province":   [guangdong],
    "address.city":  [guangzhou]
}

又比如
{
"authors": [
{ "age": 26, "name": "Jack White"},
{ "age": 55, "name": "Tom Jones"},
{ "age": 39, "name": "Kitty Smith"}
]
}
存储如下 ,底层是这样存储的

{
    "authors.age":    [26, 55, 39],
    "authors.name":   [jack, white, tom, jones, kitty, smith]
}
search api的基本语法

1、search api的基本语法

GET /search
{}

GET /index1,index2/type1,type2/search
{}

GET /_search
{
"from": 0,
"size": 10
}
HTTP协议,一般不允许get请求带上request body,但是因为get更加适合描述查询数据的操作,因此还是这么用了。

Query DSL

1、Query DSL的基本语法

{
    QUERY_NAME: {
        ARGUMENT: VALUE,
        ARGUMENT: VALUE,...
    }
}

2、如何组合多个搜索条件
搜索需求:title必须包含elasticsearch,content可以包含elasticsearch也可以不包含,author_id必须不为111
源数据如下

{
  "took": 1,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "failed": 0
  },
  "hits": {
    "total": 3,
    "max_score": 1,
    "hits": [
      {
        "_index": "website",
        "_type": "article",
        "_id": "2",
        "_score": 1,
        "_source": {
          "title": "my hadoop article",
          "content": "hadoop is very bad",
          "author_id": 111
        }
      },
      {
        "_index": "website",
        "_type": "article",
        "_id": "1",
        "_score": 1,
        "_source": {
          "title": "my elasticsearch article",
          "content": "es is very bad",
          "author_id": 110
        }
      },
      {
        "_index": "website",
        "_type": "article",
        "_id": "3",
        "_score": 1,
        "_source": {
          "title": "my elasticsearch article",
          "content": "es is very goods",
          "author_id": 111
        }
      }
    ]
  }
}

搜索语句,当需要组合搜索的时候 就加一个bool

GET /website/article/_search
{
  "query": {
    "bool": {
      "must": [
        {
          "match": {
            "title": "elasticsearch"
          }
        }
      ],
      "should": [
        {
          "match": {
            "content": "elasticsearch"
          }
        }
      ],
      "must_not": [
        {
          "match": {
            "author_id": 111
          }
        }
      ]
    }
  }
}

must 是必须,should里面的条件是满足和非满足都无所谓,minimum_should_match最小数量必须为1

GET /test_index/_search
{
    "query": {
            "bool": {
                "must": { "match":   { "name": "tom" }},
                "should": [
                    { "match":       { "hired": true }},
                    { "bool": {
                        "must":      { "match": { "personality": "good" }},
                        "must_not":  { "match": { "rude": true }}
                    }}
                ],
                "minimum_should_match": 1
            }
    }
}
filter与query对比

1 加入数据

PUT /company/employee/2
{
  "address": {
    "country": "china",
    "province": "jiangsu",
    "city": "nanjing"
  },
  "name": "tom",
  "age": 30,
  "join_date": "2016-01-01"
}

PUT /company/employee/3
{
  "address": {
    "country": "china",
    "province": "shanxi",
    "city": "xian"
  },
  "name": "marry",
  "age": 35,
  "join_date": "2015-01-01"
}

搜索请求:年龄必须大于等于30,同时join_date必须是2016-01-01

GET /company/employee/_search
{
  "query": {
    "bool": {
      "must": [
        {
          "match": {
            "join_date": "2016-01-01"
          }
        }
      ],
      "filter": {
        "range": {
          "age": {
            "gte": 30
          }
        }
      }
    }
  }
}

2、filter与query对比大解密

filter,仅仅只是按照搜索条件过滤出需要的数据而已,不计算任何相关度分数,对相关度没有任何影响
query,会去计算每个document相对于搜索条件的相关度,并按照相关度进行排序

一般来说,如果你是在进行搜索,需要将最匹配搜索条件的数据先返回,那么用query;如果你只是要根据一些条件筛选出一部分数据,不关注其排序,那么用filter
除非是你的这些搜索条件,你希望越符合这些搜索条件的document越排在前面返回,那么这些搜索条件要放在query中;如果你不希望一些搜索条件来影响你的document排序,那么就放在filter中即可

3、filter与query性能

filter,不需要计算相关度分数,不需要按照相关度分数进行排序,同时还有内置的自动cache最常使用filter的数据
query,相反,要计算相关度分数,按照分数进行排序,而且无法cache结果

query搜索语法

1、match all 查询所有数据

GET /_search
{
    "query": {
        "match_all": {}
    }
}

2、match 必须匹配该条件

GET /_search
{
    "query": { "match": { "title": "my elasticsearch article" }}
}

3、multi match 多重匹配

GET /test_index/test_type/_search
{
  "query": {
    "multi_match": {
      "query": "test",
      "fields": ["test_field", "test_field1"]
    }
  }
}

4、range query 范围查找

GET /company/employee/_search 
{
  "query": {
    "range": {
      "age": {
        "gte": 30
      }
    }
  }
}

5、term query 注意:在term 里面搜索不会去分词查询,在match 里面搜索会去分词

GET /test_index/test_type/_search 
{
  "query": {
    "term": {
      "test_field": "test hello"
    }
  }
}

6、terms query

GET /_search
{
    "query": { "terms": { "tag": [ "search", "full_text", "nosql" ] }}
}

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