Mappings for new fields can be added after a type has been created. A mapping can be updated for a type with the PUT mapping API. Let's add a code field, which is of the keyword type, but with no analysis:

PUT /catalog/_mapping
{
  "properties": {
    "code": {
      "type": "keyword"
    }
  }
}

This mapping is merged into the existing mappings of the _doc type. The mapping looks like the following after it is merged:

{
  "catalog" : {
    "mappings" : {
      "properties" : {
        "code" : {
          "type" : "keyword"
        },
        "description" : {
          "type" : "text",
          "fields" : {
            "keyword" : {
              "type" : "keyword",
              "ignore_above" : 256
            }
          }
        },
        "name" : {
          "type" : "text"
        }
      }
    }
  }
}

Any subsequent documents that are indexed with the code field are assigned the right datatype:

POST /catalog/_doc
{
  "name": "sports",
  "code": "C004",
  "description": "Sports equipment"
}

This is how we can take control of the index creation and type mapping process, and add fields after the type is created.