[[properties]]
=== `properties`

Type mappings, <<object,`object` fields>> and <<nested,`nested` fields>>
contain sub-fields, called `properties`. These properties may be of any
<<mapping-types,datatype>>, including `object` and `nested`.  Properties can
be added:

* explicitly by defining them when <<indices-create-index,creating an index>>.
* explicitly by defining them when adding or updating a mapping type with the <<indices-put-mapping,PUT mapping>> API.
* <<dynamic-mapping,dynamically>> just by indexing documents containing new fields.

Below is an example of adding `properties` to a mapping type, an `object`
field, and a `nested` field:

[source,console]
--------------------------------------------------
PUT my_index
{
  "mappings": {
    "properties": { <1>
      "manager": {
        "properties": { <2>
          "age":  { "type": "integer" },
          "name": { "type": "text"  }
        }
      },
      "employees": {
        "type": "nested",
        "properties": { <3>
          "age":  { "type": "integer" },
          "name": { "type": "text"  }
        }
      }
    }
  }
}

PUT my_index/_doc/1 <4>
{
  "region": "US",
  "manager": {
    "name": "Alice White",
    "age": 30
  },
  "employees": [
    {
      "name": "John Smith",
      "age": 34
    },
    {
      "name": "Peter Brown",
      "age": 26
    }
  ]
}
--------------------------------------------------

<1> Properties in the top-level mappings definition.
<2> Properties under the `manager` object field.
<3> Properties under the `employees` nested field.
<4> An example document which corresponds to the above mapping.

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

==== Dot notation

Inner fields can be referred to in queries, aggregations, etc., using _dot
notation_:

[source,console]
--------------------------------------------------
GET my_index/_search
{
  "query": {
    "match": {
      "manager.name": "Alice White" 
    }
  },
  "aggs": {
    "Employees": {
      "nested": {
        "path": "employees"
      },
      "aggs": {
        "Employee Ages": {
          "histogram": {
            "field": "employees.age", 
            "interval": 5
          }
        }
      }
    }
  }
}
--------------------------------------------------
// TEST[continued]

IMPORTANT: The full path to the inner field must be specified.