Elasticsearch Mapping

March 24, 2019
By MYSQLGYAN

Elasticsearch Basics

What is mapping in elasticsearch

Mapping is the process of defining how a document, and the fields it contains, are stored and indexed. For instance, use mappings to define:
- which fields contain numbers, dates, or geolocations.
- which string fields should be treated as full text fields.
- the format of date values.
- custom rules to control the mapping for dynamically added fields.

DATA TYPES IN ELASTICSEARCH

String :-

- text
- keyword

Numeric :-

- long
- integer
- short
- byte
- double
- float
- half_float
- scaled_float

date :-

- date

boolean :-

- boolean

binary :-

- binary

range :-

- integer_range
- float_range
- long_range
- double_range
- date_range

complex datatypes:-

- array
- object (for single json)
- nested (for arrays of json objects)

Geo location :-

- geo_point (for lat/long points) - geo_shape (for complex shapes like polygons)

Speciliazed datatypes :-

- IP :- ip for IPv4 and IPv6 addresses
- completion :- to provide auto-complete suggestions
- token_count :- to count the number of tokens in a string
- murmur3 :-to compute hashes of values at index-time and store them in the index
- nnotated-text :- to index text containing special markup (typically used for identifying named entities)
- percolator :-Accepts queries from the query-dsl
- join :- Defines parent/child relation for documents within the same index
- alias :-Defines an alias to an existing field.

It is often useful to index the same field in different ways for different purposes. For instance, a string field could be indexed as a text field for full-text search, and as a keyword field for sorting or aggregations. Alternatively, you could index a string field with the standard analyzer, the englishanalyzer, and the french analyzer. This is the purpose of multi-fields. Most datatypes support multi-fields via the fields parameter.

EXAMPLE MAPPING

		
curl -X PUT "localhost:9200/index_name" -H 'Content-Type: application/json' -d'
{
  "mappings": {
    "_doc": { 
      "properties": { 
        "user_id":    { "type": "integer"  }, 
        "user_name":     { "type": "text"  }, 
        "user_age":      { "type": "integer" },  
        "created":  {
          "type":   "date", 
          "format": "strict_date_optional_time||epoch_millis"
        }
      }
    }
  }
}
'