The data modeling language
The need for data storage has always been there since the existence of VisiCalc, the historic and killer spreadsheet program. Then came along databases with their relational models. Various vendors for the same popped up, and, right now, RDBMS is the most widely used paradigm for data storage. Many solutions exist, ranging from the lightest, SQLite, to the heaviest, Oracle, with SQLServer, MySQL, and Postgres in between.
To query and process data, a language called Structured Query Language (SQL) has also evolved. We currently have many dialects of this language that vary from vendor to vendor, although many standard bodies and standards exist for SQL.
Initially, each database software had its own low-level protocol. SQL and the results of the executed SQL would be communicated over this protocol. So, you required a special piece of software that could talk to your database, and this software was called a database driver. Then, the story of Connectivity Standards...