For questions about mapping in Elasticsearch; the process of defining how a document should be mapped to the index.
In elasticsearch, an index may store documents of different "mapping types". elasticsearch allows one to associate multiple mapping definitions for each mapping type.
Explicit mapping is defined on an index/type level. By default, there isn’t a need to define an explicit mapping, since one is automatically created and registered when a new type or new field is introduced (with no performance overhead) and have sensible defaults. Only when the defaults need to be overridden must a mapping definition be provided.
