You can define how documents and their fields are stored and indexed by creating a _mapping_. The mapping specifies the list of fields for a document. Every field in the document has a _field type_, which corresponds to the type of data the field contains. For example, you may want to specify that the `year` field should be of type `date`. To learn more, see [Supported field types]({{site.url}}{{site.baseurl}}/field-types/supported-field-types/index/).
If you're just starting to build out your cluster and data, you may not know exactly how your data should be stored. In those cases, you can use dynamic mappings, which tell OpenSearch to dynamically add data and its fields. However, if you know exactly what types your data falls under and want to enforce that standard, then you can use explicit mappings.
For example, if you want to indicate that `year` should be of type `text` instead of an `integer`, and `age` should be an `integer`, you can do so with explicit mappings. By using dynamic mapping, OpenSearch might interpret both `year` and `age` as integers.
This section provides an example for how to create an index mapping and how to add a document to it that will get ip_range validated.
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## Dynamic mapping
When you index a document, OpenSearch adds fields automatically with dynamic mapping. You can also explicitly add fields to an index mapping.
#### Dynamic mapping types
Type | Description
:--- | :---
null | A `null` field can't be indexed or searched. When a field is set to null, OpenSearch behaves as if that field has no values.
boolean | OpenSearch accepts `true` and `false` as boolean values. An empty string is equal to `false.`
float | A single-precision 32-bit floating point number.
double | A double-precision 64-bit floating point number.
integer | A signed 32-bit number.
object | Objects are standard JSON objects, which can have fields and mappings of their own. For example, a `movies` object can have additional properties such as `title`, `year`, and `director`.
array | Arrays in OpenSearch can only store values of one type, such as an array of just integers or strings. Empty arrays are treated as though they are fields with no values.
text | A string sequence of characters that represent full-text values.
keyword | A string sequence of structured characters, such as an email address or ZIP code.
date detection string | Enabled by default, if new string fields match a date's format, then the string is processed as a `date` field. For example, `date: "2012/03/11"` is processed as a date.
numeric detection string | If disabled, OpenSearch may automatically process numeric values as strings when they should be processed as numbers. When enabled, OpenSearch can process strings into `long`, `integer`, `short`, `byte`, `double`, `float`, `half_float`, `scaled_float`, and `unsigned_long`. Default is disabled.
## Explicit mapping
If you know exactly what your field data types need to be, you can specify them in your request body when creating your index.
You cannot change the mapping of an existing field, you can only modify the field's mapping parameters.
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## Mapping example usage
The following example shows how to create a mapping to specify that OpenSearch should ignore any documents with malformed IP addresses that do not conform to the [`ip`]({{site.url}}{{site.baseurl}}/opensearch/supported-field-types/ip/) data type. You accomplish this by setting the `ignore_malformed` parameter to `true`.
