i want to search for documents that field exists only search term in elasticsearch

Question

part of my document mapping below:

"character_cut": {
  "type": "keyword"
}

and sample data is here.

doc1 character_cut: ["John"]

doc2 character_cut: ["John", "Smith"]

doc3 character_cut: ["Smith", "Jessica", "Anna"]

doc4 character_cut: ["John"]

if i find "John" will retrive doc1, doc2, doc4.

how can i retrive only doc1, doc4 with "John" query?

Answer 1

There are 2 ways to do it.

1. Token_count

A field of type token_count is really an integer field which accepts string values, analyzes them, then indexes the number of tokens in the string.

PUT index-name
{
  "mappings": {
    "properties": {
      "character_cut":{
        "type": "text",
        "fields": {
          "keyword":{
            "type":"keyword"
          },
          "length":{
            "type":"token_count", ---> no of keyword tokens
            "analyzer":"keyword"
          }
        }
      }
    }
  }
}

Query

{
  "query": {
    "bool": {
      "must": [
        {
          "term": {
            "character_cut.keyword": {
              "value": "John"
            }
          }
        },
        {
         "term": {
           "character_cut.length": {
             "value": 1    --> replace with no of  matches required
           }
         }
        }
      ]
    }
  }
}

2. Using script query

{
  "query": {
    "bool": {
      "must": [
        {
          "term": {
            "character_cut.keyword": {
              "value": "John"
            }
          }
        },
        {
         "script": {
           "script": "doc['character_cut.keyword'].size()==1"
                                   --> replace with no of  matches required
         }
        }
      ]
    }
  }
}

token_count will calculate count at index time so it will be faster than script which will compute at run time