Elasticsearch article describes the Search API

1 SearchAPI Overview

Es realize the data stored in the analysis, endpoint is _search, as follows:
Here Insert Picture Description
Query There are two main forms of

2 URISearch explain and demonstrate

Achieved by url query search parameters, the following common parameters:

q specify the query statement, the syntax for the Query String Syntax
df q default field queries without the specified field, if not specified, es queries all fields
sort sort
timeout specified timeout, no timeout default
from, size used for pagination
term 与 phrase
- alfred way equivalent to alfred or way
- "Alfred way" words in the query, the requirements have to sort
Pan inquiry
- alfred equivalent to the term to match in all fields
The specified field
- name:aflred
Group set packet, a matching rule specified parentheses
- (quick OR brown)AND fox
- status: (active OR pending) title : (full text search)
  to create an index, generate test documents

PUT my_index_search
{
  "settings": 
  {
    "number_of_shards": "5",
    "number_of_replicas": "0"
  }
}
POST my_index_search/doc/_bulk
{"index":{"_id": "1"}}
{"username": "alfred way","job": "java engineer","age": 18,"birth": "1990-01-02","isMarried":false}
{"index":{"_id": "2"}}
{"username": "alfred","job": "java senior and java specialist","age": 28,"birth": "1980-05-07","isMarried":true}
{"index":{"_id": "3"}}
{"username": "lee","job": "java and ruby engineer","age": 22,"birth": "1985-08-07","isMarried":false}
{"index":{"_id": "4"}}
{"username": "alfred junior way","job": "ruby engineer","age": 23,"birth": "1989-08-02","isMarried":false}

# 查询所有字段中有alfred的文档
GET my_index_search/_search?q=alfred
# 设置profile可以看具体的查询语句
GET my_index_search/_search?q=alfred
{
  "profile": true
}
GET my_index_search/_search?q=username:alfred
GET my_index_search/_search?q=username:alfred
{
  "profile": true
}
# username:alfred和way是OR的关系
GET my_index_search/_search?q=username:alfred way
{
  "profile": true
}
# PhraseQuery词语的查询
GET my_index_search/_search?q=username:"alfred way"
{
  "profile": true
}
# "description": "username:alfred username:way" 下面描述
GET my_index_search/_search?q=username:(alfred way)
{
  "profile": true
}

Boolean operators
AND(&&) OR(||) NOT(!)
name:(tom NOT lee)
Note uppercase, lowercase can not
+ - and respectively must must_not
name:(tom +lee -alfred) 或者 name:((lee && !alfred)||(tome && lee && !alfred))
+ In the url will be resolved to a space, before they can be used encode for% 2B

GET my_index_search/_search?q=username:alfred AND way
{
  "profile": true
}
GET my_index_search/_search?q=username:(alfred AND way)
{
  "profile": true
}
GET my_index_search/_search?q=username:(alfred NOT way)
{
  "profile": true
}
GET my_index_search/_search?q=username:(alfred +way)
{
  "profile": true
}
GET my_index_search/_search?q=username:(alfred %2Bway)
{
  "profile": true
}

Range queries, support and value date
- Writing interval, a closed interval [] {} open interval
  - age: [1 TO 10] I为 1 <= age <= 10
  - age: [1 TO 10} I为 1 <= age <10
  - age: [1 TO] I为 age> = 1
  - age: {* TO 10] I为 age <= 10
- Arithmetic sign writing
  - age:>=1
  - age:(>=1 && <=10)或者 age:(+>=1 +<=10)

GET my_index_search/_search?q=username:alfred age:>20
GET my_index_search/_search?q=username:alfred AND age:>20
GET my_index_search/_search?q=birth:(>1980 AND <1990)

Wildcard queries
? On behalf of one character, * represents 0 or more characters
- name:t?m
- name:tom*
- name:t*m
Low wildcard matching efficiency, and take up more memory, not recommended
If no special needs, do not? / * On the front

GET my_index_search/_search?q=username:alf*

Regular expression match

GET my_index_search/_search?q=username:/[a]?l.*/

Fuzzy matching fuzzy query
name：roam~1
A matching difference roam character word, such as foam, roams etc.
Approximation proximity search query
“fox quick”~5
To compare the difference in term units, such as "quick fox" "quick brown fox" will be matched

GET my_index_search/_search?q=username:alfed~1
GET my_index_search/_search?q=job:"java engineer"~2

3 QueryDSL Profile

The query is sent to es via http request body, contains the following main parameters:

query syntax in line with Query DSL query
from、size
timeout
sort
…
JSON-based query language defined, mainly includes the following two types:
- Query class field
  - Such as term, math, range, etc., only a query against a field
- Match the query
  - The bool query, comprising one or more fields or queries type compound queries

4 Introduction class field inquiries and match-query

Query class field include the following categories:
Full match
- Full-text search for text type of field, the query would first be word processing, such as match, match_phrase and other query types
Word Match
- Will not do word processing on the query, go directly to the inverted index matching fields, such as term, terms, range and other query types
On the field for full-text search, the most basic and common type of query, API examples are as follows:

GET my_index_search/_search
{
  "query": {
    "match": {
      "username": "alfred way"
    }
  }
}
# 查看查询语句
GET my_index_search/_search
{
  "profile": true,
  "query": {
    "match": {
      "username": "alfred way"
    }
  }
}

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You can control the relationship between words by matching operator parameters, options or and and

GET my_index_search/_search
{
  "profile": true,
  "query": {
    "match": {
      "username": {
        "query": "alfred way",
        "operator": "and"
      }
    }
  }
}

Minmun_should_match parameters can be controlled by the need to match the number of words

GET my_index_search/_search
{
  "profile": true,
  "query": {
    "match": {
      "job": {
        "query": "java ruby engineer",
        "minimum_should_match": 2
      }
    }
  }
}

Correlation calculation points 5

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Correlation count points refers to the degree of correlation between the document and the query, English as relevance
- You can get a list of documents that match the query by inverted index
- Is essentially a scheduling problem, ordering is based on the correlation count points
Several important concepts of count points as follows:
- Term Frequency (TF) word frequency, that is, the number of occurrences of the word in the document. The higher the word frequency, the higher the degree of correlation
- Document Frequency (DF) document frequency, that word appears in the document tree
- Inverse Document Frequency (IDF) inverse document frequency, document frequency contrast, simply understood as 1 / DF. That is, the fewer the number of documents occurrences of the word, the more relevant
- Field-length Norm document shorter, more relevant
ES At present, there are two related points of calculation models, such as:
- TF / IDF model
- The default model after model BM25 5.x

6 match-phrase-query

Field for retrieval, sequential requirements, as an example of the API

GET my_index_search/_search
{
  "profile": true,
  "query": {
    "match_phrase": {
      "job": {
        "query": "java engineer"
      }
    }
  }
}
GET my_index_search/_search
{
  "profile": true,
  "query": {
    "match_phrase": {
      "job": {
        "query": "engineer java"
      }
    }
  }
}
GET my_index_search/_search
{
  "profile": true,
  "query": {
    "match_phrase": {
      "job": {
        "query": "java engineer",
        "slop": 1
      }
    }
  }
}

GET my_index_search/_search
{
  "profile": true,
  "query": {
    "match_phrase": {
      "job": {
        "query": "java engineer",
        "slop": 2
      }
    }
  }
}

7 query-string-query

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GET my_index_search/_search
{
  "query": {
    "query_string": {
      "default_field": "username",
      "query": "alfred AND way"
    }
  }
}
GET my_index_search/_search
{
  "profile": true,
  "query": {
    "query_string": {
      "fields": [
          "username",
          "job"
        ],
      "query": "alfred OR (java AND ruby)"
    }
  }
}

8 simple-query-string-query

Similarly Query String, but ignores the query syntax error, and supports only part of the query syntax
As commonly used systems which can not use AND, OR, NOT, etc. Keywords:
- On behalf of that AND +
- | On behalf of that OR
- - on behalf of that NOT

# 必须包含away，可以包含alfred
GET my_index_search/_search
{
  "profile": true,
  "query": {
    "simple_query_string": {
      "query": "alfred +way",
      "fields": ["username"]
    }
  }
}
GET my_index_search/_search
{
  "profile": true,
  "query": {
    "simple_query_string": {
      "query": "alfred +way AND java",
      "fields": ["username"]
    }
  }
}

Comparison of query_string and simple_query_string

GET my_index_search/_search
{
  "profile": true,
  "query": {
    "query_string": {
      "fields": ["username"],
      "query": "alfred OR (\"java AND ruby)"
    }
  }
}
GET my_index_search/_search
{
  "profile": true,
  "query": {
    "simple_query_string": {
      "query": "alfred +way AND \"java",
      "fields": ["username"]
    }
  }
}

9 term/terms-query

The term-query query query as a whole word, that word did not query processing, as follows:
terms-query once passed more than one word query, as follows:

# term query
GET my_index_search/_search
{
  "profile": true,
  "query": {
    "term": {
      "username": "alfred"
    }
  }
}
GET my_index_search/_search
{
  "profile": true,
  "query": {
    "term": {
      "username": "alfred way"
    }
  }
}
# terms query
GET my_index_search/_search
{
  "profile": true,
  "query": {
    "terms": {
      "username": [
        "alfred",
        "way"
      ]
    }
  }
}

10 range-query

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GET my_index_search/_search
{
  "query": {
    "range": {
      "age": {
        "gte": 10,
        "lte": 20
      }
    }
  }
}
GET my_index_search/_search
{
  "query": {
    "range": {
      "birth": {
        "gte": "1980-01-01"
      }
    }
  }
}
GET my_index_search/_search
{
  "query": {
    "range": {
      "birth": {
        "gte": "now-35y"
      }
    }
  }
}