1, in Elasticsearch, a document belonging to one type (of the type) , and these types exist in the index (index) , we can draw some simple comparison chart to a traditional relational database analogy:
Relational DB -> Databases -> Tables -> Rows -> Columns
Elasticsearch -> Indices -> Types -> Documents -> Fields
Namely: Elasticsearch cluster may comprise a plurality of indices (indices) (database), each index may comprise a plurality of types (types) (Table), each containing a plurality of types of documents (Documents) (OK), then each document comprising a plurality of fields (fields) (column).