DBMS stores data as files while RDBMS stores data in tabular form with relationships between tables. DBMS is meant for small organizations and single users, does not support normalization, and lacks security features. RDBMS supports large data, multiple users, normalization, security, distributed databases, and examples include MySQL, PostgreSQL, and Oracle. The key difference is that RDBMS represents data in tables with relationships while DBMS stores data as files without relationships.