copy_to

edit

The copy_to parameter allows you to create custom _all fields. In other words, the values of multiple fields can be copied into a group field, which can then be queried as a single field. For instance, the first_name and last_name fields can be copied to the full_name field as follows:

PUT /my_index
{
  "mappings": {
    "my_type": {
      "properties": {
        "first_name": {
          "type": "string",
          "copy_to": "full_name" 
        },
        "last_name": {
          "type": "string",
          "copy_to": "full_name" 
        },
        "full_name": {
          "type": "string"
        }
      }
    }
  }
}

PUT /my_index/my_type/1
{
  "first_name": "John",
  "last_name": "Smith"
}

GET /my_index/_search
{
  "query": {
    "match": {
      "full_name": { 
        "query": "John Smith",
        "operator": "and"
      }
    }
  }
}

The values of the first_name and last_name fields are copied to the full_name field.

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" ]