A database server may refer to both hardware and software used to run a database. It is basically a computer program or a dedicated system that caters database services to other computer programs or computers, as defined by the client–server model.
The base of Query Language is a vital part of database servers. Each database understands, converts it to Server readable form and executes it to retrieve the results. The SQL query language is more or less the same in all relational database servers. DB-Engines lists over 200 DBMSs in its ranking.
Oracle, DB2, Informix, and Microsoft SQL Server are few of the best examples of proprietary database servers. Every server uses its own query logic and structure.