I. Basic information

Preface: term query and match query involve many things, such as word segmentation, mapping, inverted index and so on. I would like to take an example from an official document to talk about my understanding of this place.

• The string type in es5. * is divided into text and keyword. Text is to be segmented, and the whole string is decomposed into a lowercase term according to certain rules. keyword is similar to the case of not_analyzed in es2.3.

• term query looks for the exact term in the inverted index, and it does not know the existence of the word segmentation. This query is suitable for keyword, numeric, date
• match query knows the existence of word segmentation. And understand how words are segmented.

Overall, there are the following:
- term query queries the exact term in the inverted index
- match query performs word segmentation on files and then queries

Testing (1)

1. Prepare data:

POST /termtest/termtype/1
{
  "content":"Name"
}

POST /termtest/termtype/2
{
  "content":"name city"
}

1. Check whether the data is imported or not

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

•  

• Result:

{
  "took": 1,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "failed": 0
  },
  "hits": {
    "total": 2,
    "max_score": 1,
    "hits": [
      {
        "_index": "termtest",
        "_type": "termtype",
        "_id": "2",
        "_score": 1,
        "_source": {
          "content": "name city"
        }
      },
      {
        "_index": "termtest",
        "_type": "termtype",
        "_id": "1",
        "_score": 1,
        "_source": {
          "content": "Name"
        }
      }
    ]
  }
}

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1. Make the following queries:

POST /termtest/_search
{
  "query":{
    "term":{
      "content":"Name"
    }
  }
}

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• Result

{
  "took": 1,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "failed": 0
  },
  "hits": {
    "total": 0,
    "max_score": null,
    "hits": []
  }
}

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POST /termtest/_search
{
  "query":{
    "match":{
      "content":"Name"
    }
  }
}

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• Result

{
  "took": 2,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "failed": 0
  },
  "hits": {
    "total": 2,
    "max_score": 0.2876821,
    "hits": [
      {
        "_index": "termtest",
        "_type": "termtype",
        "_id": "1",
        "_score": 0.2876821,
        "_source": {
          "content": "Name"
        }
      },
      {
        "_index": "termtest",
        "_type": "termtype",
        "_id": "2",
        "_score": 0.25811607,
        "_source": {
          "content": "name city"
        }
      }
    ]
  }
}

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3. Testing (2)

Here's an example of the official website Official website instance 
1. Importing data

PUT my_index
{
  "mappings": {
    "my_type": {
      "properties": {
        "full_text": {
          "type":  "text" 
        },
        "exact_value": {
          "type":  "keyword" 
        }
      }
    }
  }
}

PUT my_index/my_type/1
{
  "full_text":   "Quick Foxes!", 
  "exact_value": "Quick Foxes!"  
}

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• full_text: Specifies a type of text, which is participled.
• exact_value: Specifies a type of keyword that will not be participled
• full_text: Subjected to standard analyzer, the following terms [quick,foxes] are stored in the inverted index

• exact_value: Only the term [Quick Foxes!] will be stored in the inverted index

  1. Make the following query

GET my_index/my_type/_search
{
  "query": {
    "term": {
      "exact_value": "Quick Foxes!" 
    }
  }
}

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Result:

{
  "took": 1,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "failed": 0
  },
  "hits": {
    "total": 1,
    "max_score": 0.2876821,
    "hits": [
      {
        "_index": "my_index",
        "_type": "my_type",
        "_id": "1",
        "_score": 0.2876821,
        "_source": {
          "full_text": "Quick Foxes!",
          "exact_value": "Quick Foxes!"
        }
      }
    ]
  }
}

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GET my_index/my_type/_search
{
  "query": {
    "term": {
      "full_text": "Quick Foxes!" 
    }
  }
}

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Result:

{
  "took": 4,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "failed": 0
  },
  "hits": {
    "total": 0,
    "max_score": null,
    "hits": []
  }
}

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GET my_index/my_type/_search
{
  "query": {
    "term": {
      "full_text": "foxes" 
    }
  }
}

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Result:

{
  "took": 2,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "failed": 0
  },
  "hits": {
    "total": 1,
    "max_score": 0.25811607,
    "hits": [
      {
        "_index": "my_index",
        "_type": "my_type",
        "_id": "1",
        "_score": 0.25811607,
        "_source": {
          "full_text": "Quick Foxes!",
          "exact_value": "Quick Foxes!"
        }
      }
    ]
  }
}

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GET my_index/my_type/_search
{
  "query": {
    "match": {
      "full_text": "Quick Foxes!" 
    }
  }
}

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Result:

{
  "took": 3,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "failed": 0
  },
  "hits": {
    "total": 1,
    "max_score": 0.51623213,
    "hits": [
      {
        "_index": "my_index",
        "_type": "my_type",
        "_id": "1",
        "_score": 0.51623213,
        "_source": {
          "full_text": "Quick Foxes!",
          "exact_value": "Quick Foxes!"
        }
      }
    ]
  }
}

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