Generic Data Structure Standards Relational databases are the most common way of storing data, and there is universal agreement that data in relational databases is structured data. Other important forms of structured data, at least according to some practitioners, are spreadsheets and Comma-Separated Value (CSV) files, Resource Description Framework (RDF) triple stores, JavaScript™ Object Notation (JSON) and YAML (a recursive acronym for “YAML Ain’t Markup Language”) files, Extensible Markup Language (XML) files, and text files in Backus-Naur Form (BNF).