[[one-lang-fields]] === One Language per Field
For documents that represent entities like products, movies, or legal notices, it is common((("fields", "one language per field")))((("languages", "one language per field"))) for the same text to be translated into several languages. Although each translation could be represented in a single document in an index per language, another reasonable approach is to keep all translations in the same document:
[source,js]
{ "title": "Fight club", "title_br": "Clube de Luta", "title_cz": "Klub rvácu", "title_en": "Fight club", "title_es": "El club de la lucha", ...
}
Each translation is stored in a separate field, which is analyzed according to the language it contains:
[source,js]
PUT /movies { "mappings": { "movie": { "properties": { "title": { <1> "type": "string" }, "title_br": { <2> "type": "string", "analyzer": "brazilian" }, "title_cz": { <2> "type": "string", "analyzer": "czech" }, "title_en": { <2> "type": "string", "analyzer": "english" }, "title_es": { <2> "type": "string", "analyzer": "spanish" } } } }
}
<1> The title field contains the original title and uses the
standard analyzer.
<2> Each of the other fields uses the appropriate analyzer for that language.
Like the index-per-language approach, the field-per-language approach
maintains clean term frequencies. It is not quite as flexible as having
separate indices. Although it is easy to add a new field by using the <
The documents of a((("boosting", "query-time", "boosting a field"))) single language can be queried independently, or queries can target multiple languages by querying multiple fields. We can even specify a preference for particular languages by boosting that field:
[source,js]
GET /movies/movie/_search { "query": { "multi_match": { "query": "club de la lucha", "fields": [ "title*", "title_es^2" ], <1> "type": "most_fields" } }
}
<1> This search queries any field beginning with title but
boosts the title_es field by 2. All other fields have
a neutral boost of 1.