Dynamic field mappingedit

When Elasticsearch detects a new field in a document, it dynamically adds the field to the type mapping by default. The dynamic parameter controls this behavior.

You can explicitly instruct Elasticsearch to dynamically create fields based on incoming documents by setting the dynamic parameter to true or runtime. When dynamic field mapping is enabled, Elasticsearch uses the rules in the following table to determine how to map data types for each field.

The field data types in the following table are the only field data types that Elasticsearch detects dynamically. You must explicitly map all other data types.

JSON data type

"dynamic":"true"

"dynamic":"runtime"

null

No field added

No field added

true or false

boolean

boolean

double

float

double

integer

long

long

object

object

No field added

array

Depends on the first non-null value in the array

Depends on the first non-null value in the array

string that passes date detection

date

date

string that passes numeric detection

float or long

double or long

string that doesn’t pass date detection or numeric detection

text with a .keyword sub-field

keyword

You can disable dynamic mapping, both at the document and at the object level. Setting the dynamic parameter to false ignores new fields, and strict rejects the document if Elasticsearch encounters an unknown field.

Use the update mapping API to update the dynamic setting on existing fields.

You can customize dynamic field mapping rules for date detection and numeric detection. To define custom mappings rules that you can apply to additional dynamic fields, use dynamic_templates.

Date detectionedit

If date_detection is enabled (default), then new string fields are checked to see whether their contents match any of the date patterns specified in dynamic_date_formats. If a match is found, a new date field is added with the corresponding format.

The default value for dynamic_date_formats is:

[ "strict_date_optional_time","yyyy/MM/dd HH:mm:ss Z||yyyy/MM/dd Z"]

For example:

PUT my-index-000001/_doc/1
{
  "create_date": "2015/09/02"
}

GET my-index-000001/_mapping 

The create_date field has been added as a date field with the format:
"yyyy/MM/dd HH:mm:ss Z||yyyy/MM/dd Z".

Disabling date detectionedit

Dynamic date detection can be disabled by setting date_detection to false:

PUT my-index-000001
{
  "mappings": {
    "date_detection": false
  }
}

PUT my-index-000001/_doc/1 
{
  "create_date": "2015/09/02"
}

The create_date field has been added as a text field.

Customizing detected date formatsedit

Alternatively, the dynamic_date_formats can be customized to support your own date formats:

PUT my-index-000001
{
  "mappings": {
    "dynamic_date_formats": ["MM/dd/yyyy"]
  }
}

PUT my-index-000001/_doc/1
{
  "create_date": "09/25/2015"
}

Numeric detectionedit

While JSON has support for native floating point and integer data types, some applications or languages may sometimes render numbers as strings. Usually the correct solution is to map these fields explicitly, but numeric detection (which is disabled by default) can be enabled to do this automatically:

PUT my-index-000001
{
  "mappings": {
    "numeric_detection": true
  }
}

PUT my-index-000001/_doc/1
{
  "my_float":   "1.0", 
  "my_integer": "1" 
}

The my_float field is added as a float field.

The my_integer field is added as a long field.