Mapping - Elastcisearch

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"
        }
      }
    }
  }
}
'