The DBMS acronym means Data Base Management System. So any graphic interface that helps on the database management can be considered a DBMS.
The mainly function of a DBMS is make easier for the client the access to commands related to maintenance, creation or manipulation of an already existed database. For example we can quote the SQL Enterprise which is a very friendly interface responsible to make tasks related to databases.
As mainly attributes we can highlight the creation, edition and exclusion of a base, charts and procedures in cases where the database supports them. Another common task is the execution of commands that manipulates data on tables like the consults ones, inclusion, exclusion and actualization. Besides, routine task like backup creation and logs analysis also makes the DBMS job qualifications.
The DBMS is a practice and fast resource for those who wish to work with a database. Practically every database available on market uses their own that helps to manage the database. That been said, analyze your needs, choose the database that you judges better and use the DBMS to get much more results!