[[mapping]]
= Mapping

[partintro]
--
Mapping is the process of defining how a document should be mapped to
the Search Engine, including its searchable characteristics such as
which fields are searchable and if/how they are tokenized. In
Elasticsearch, an index may store documents of different "mapping
types". Elasticsearch allows one to associate multiple mapping
definitions for each mapping type.

Explicit mapping is defined on an index/type level. By default, there
isn't a need to define an explicit mapping, since one is automatically
created and registered when a new type or new field is introduced (with
no performance overhead) and have sensible defaults. Only when the
defaults need to be overridden must a mapping definition be provided.

[float]
[[all-mapping-types]]
=== Mapping Types

Mapping types are a way to divide the documents in an index into logical
groups. Think of it as tables in a database. Though there is separation
between types, it's not a full separation (all end up as a document
within the same Lucene index).

Field names with the same name across types are highly recommended to
have the same type and same mapping characteristics (analysis settings
for example). There is an effort to allow to explicitly "choose" which
field to use by using type prefix (`my_type.my_field`), but it's not
complete, and there are places where it will never work (like faceting
on the field).

In practice though, this restriction is almost never an issue. The field
name usually ends up being a good indication to its "typeness" (e.g.
"first_name" will always be a string). Note also, that this does not
apply to the cross index case.

[float]
[[mapping-api]]
=== Mapping API

To create a mapping, you will need the <<indices-put-mapping,Put Mapping
API>>, or you can add multiple mappings when you <<indices-create-index,create an
index>>.

[float]
[[mapping-settings]]
=== Global Settings

The `index.mapping.ignore_malformed` global setting can be set on the
index level to allow to ignore malformed content globally across all
mapping types (malformed content example is trying to index a text string
value as a numeric type).

The `index.mapping.coerce` global setting can be set on the
index level to coerce numeric content globally across all
mapping types (The default setting is true and coercions attempted are 
to convert strings with numbers into numeric types and also numeric values
with fractions to any integer/short/long values minus the fraction part).
When the permitted conversions fail in their attempts, the value is considered 
malformed and the ignore_malformed setting dictates what will happen next.
--

include::mapping/fields.asciidoc[]

include::mapping/types.asciidoc[]

include::mapping/date-format.asciidoc[]

include::mapping/dynamic-mapping.asciidoc[]

include::mapping/conf-mappings.asciidoc[]

include::mapping/meta.asciidoc[]

