copy_to

The copy_to parameter allows you to copy the values of multiple fields into a group field, which can then be queried as a single field.

For example, the first_name and last_name fields can be copied to the full_name field as follows:

 PUT my-index-000001 { "mappings": { "properties": { "first_name": { "type": "text", "copy_to": "full_name" }, "last_name": { "type": "text", "copy_to": "full_name" }, "full_name": { "type": "text" } } } } PUT my-index-000001/_doc/1 { "first_name": "John", "last_name": "Smith" } GET my-index-000001/_search { "query": { "match": { "full_name": { "query": "John Smith", "operator": "and" } } } } 

1. The values of the first_name and last_name fields are copied to the full_name field.
2. The first_name and last_name fields can still be queried for the first name and last name respectively, but the full_name field can be queried for both first and last names.

Some important points:

• It is the field value which is copied, not the terms (which result from the analysis process).

• The original _source field will not be modified to show the copied values.

• The same value can be copied to multiple fields, with "copy_to": [ "field_1", "field_2" ]

• You cannot copy recursively using intermediary fields. The following configuration will not copy data from field_1 to field_3:

   PUT bad_example_index { "mappings": { "properties": { "field_1": { "type": "text", "copy_to": "field_2" }, "field_2": { "type": "text", "copy_to": "field_3" }, "field_3": { "type": "text" } } } } 

  Instead, copy to multiple fields from the source field:

   PUT good_example_index { "mappings": { "properties": { "field_1": { "type": "text", "copy_to": ["field_2", "field_3"] }, "field_2": { "type": "text" }, "field_3": { "type": "text" } } } } 

Consider the following points when using copy_to with dynamic mappings:

• If the target field does not exist in the index mappings, the usual dynamic mapping behavior applies. By default, with dynamic set to true, a non-existent target field will be dynamically added to the index mappings.

• If dynamic is set to false, the target field will not be added to the index mappings, and the value will not be copied.

• If dynamic is set to strict, copying to a non-existent field will result in an error.

• If the target field is nested, then copy_to fields must specify the full path to the nested field. Omitting the full path will lead to a strict_dynamic_mapping_exception. Use "copy_to": ["parent_field.child_field"] to correctly target a nested field.

  For example:

   PUT /test_index { "mappings": { "dynamic": "strict", "properties": { "description": { "properties": { "notes": { "type": "text", "copy_to": [ "description.notes_raw"], "analyzer": "standard", "search_analyzer": "standard" }, "notes_raw": { "type": "keyword" } } } } } } 

  1. The notes field is copied to the notes_raw field. Targeting notes_raw alone instead of description.notes_raw would lead to a strict_dynamic_mapping_exception.In this example, notes_raw is not defined at the root of the mapping, but under the description field. Without the fully qualified path, Elasticsearch would interpret the copy_to target as a root-level field, not as a nested field under description.