[[coerce]]
=== `coerce`

Data is not always clean.  Depending on how it is produced a number might be
rendered in the JSON body as a true JSON number, e.g. `5`, but it might also
be rendered as a string, e.g. `"5"`.  Alternatively, a number that should be
an integer might instead be rendered as a floating point, e.g. `5.0`, or even
`"5.0"`.

Coercion attempts to clean up dirty values to fit the datatype of a field.
For instance:

* Strings will be coerced to numbers.
* Floating points will be truncated for integer values.

For instance:

[source,js]
--------------------------------------------------
PUT my_index
{
  "mappings": {
    "properties": {
      "number_one": {
        "type": "integer"
      },
      "number_two": {
        "type": "integer",
        "coerce": false
      }
    }
  }
}

PUT my_index/_doc/1
{
  "number_one": "10" <1>
}

PUT my_index/_doc/2
{
  "number_two": "10" <2>
}
--------------------------------------------------
// CONSOLE
// TEST[catch:bad_request]
<1> The `number_one` field will contain the integer `10`.
<2> This document will be rejected because coercion is disabled.

TIP: The `coerce` setting is allowed to have different settings for fields of
the same name in the same index.  Its value can be updated on existing fields
using the <<indices-put-mapping,PUT mapping API>>.

[[coerce-setting]]
==== Index-level default

The `index.mapping.coerce` setting can be set on the index level to disable
coercion globally across all mapping types:

[source,js]
--------------------------------------------------
PUT my_index
{
  "settings": {
    "index.mapping.coerce": false
  },
  "mappings": {
    "properties": {
      "number_one": {
        "type": "integer",
        "coerce": true
      },
      "number_two": {
        "type": "integer"
      }
    }
  }
}

PUT my_index/_doc/1
{ "number_one": "10" } <1>

PUT my_index/_doc/2
{ "number_two": "10" } <2>
--------------------------------------------------
// CONSOLE
// TEST[catch:bad_request]
<1> The `number_one` field overrides the index level setting to enable coercion.
<2> This document will be rejected because the `number_two` field inherits the index-level coercion setting.