In Elasticsearch, can I set language-specific multi-fields?

Question

Is it possible to use multi-fields to set and query multilingual fields?

Consider this mapping:

PUT multi_test
{
  "mappings": {
    "data": {
      "_field_names": {
        "enabled": false
      },
      "properties": {
        "book_title": {
          "type": "text",
          "fields": {
            "english": {
              "type": "text",
              "analyzer": "english"
            },
            "german": {
              "type": "text",
              "analyzer": "german"
            },
            "italian": {
              "type": "text",
              "analyzer": "italian"
            }
          }
        }
      }
    }
  }
}

I tried the following, but it doesn't work:

PUT multi_test/data/1
{
  "book_title.english": "It's good",
  "book_title.german": "Das gut"
}

The error seems to indicate I'm trying to add new fields:

{ "error": { "root_cause": [ { "type": "mapper_parsing_exception", "reason": "Could not dynamically add mapping for field [book_title.english]. Existing mapping for [book_title] must be of type object but found [text]." } ], "type": "mapper_parsing_exception", "reason": "Could not dynamically add mapping for field [book_title.english]. Existing mapping for [book_title] must be of type object but found [text]." }, "status": 400 }

What am I doing wrong here?

If my approach is unworkable, what is a better way to do this?

Answer 1

The problem is that you are using using fields for the field book_title.

• Fields keyword is used when you want to keep same field and data in multiple ways i.e using different analyzers or some other setting changes but values should be same in all field names under fields.Here is the link describing what is keyword fields https://www.elastic.co/guide/en/elasticsearch/reference/2.4/multi-fields.html

In you use case the mapping should be like below

PUT multi_test

{
  "mappings": {
    "data": {
      "_field_names": {
        "enabled": false
      },
      "properties": {
        "book_title": {
          "properties": {
            "english": {
              "type": "text",
              "analyzer": "english"
            },
            "german": {
              "type": "text",
              "analyzer": "german"
            },
            "italian": {
              "type": "text",
              "analyzer": "italian"
            }
          }
        }
      }
    }
  }
}

This will define book_title as object type and you can add multiple fields with different data under book_title