What is a SQL database?
A SQL (pronounced “ess que el” or “sequel”) database is a system that stores, accesses and retrieves data using the SQL language. The most common type of SQL database is the relational database management systems (RDBMS) as they were among the first systems to use SQL.
Because the SQL language is so widely known and used, many modern non-relational databases, and even so-called “NoSQL” databases provide SQL interfaces for developers and users.