DBMS is Database Management System. When data is kept with some logic, retrieval and insertion becomes fast. Then database is called Relational DBMS i.e RDBMS. In RDBMS, we can apply constraints and can normalize table and can associate with other table by foreign key. In the today's market, strongest RDBMS is Oracle and latest oracle version is Oracle 12 c. Microsoft SQL Server is also a RDBMS.