US Patent 9760571 Tabular DB interface for unstructured data

A tabular (relational) DB interface is responsive to SQL commands for accessing unstructured data bases. An application receives a relational data command or query and maps fields from the relational query to fields in an unstructured data store including documents arranged in a hierarchy and unbounded by fixed types or field lengths. The application generates field names by concatenating nested hierarchy field names to define unique “flat file” field names in a tabular form. The application generates a catalog defining the mapping which is used as metadata for accessing the unstructured data to satisfy the relational query. Use of the metadata avoids copying or translating the unstructured data store to a tabular form because the unstructured data collection remains unmodified, and is accessed via the catalog.