A database management system (DBMS) is a software tool that allows arranging data in a database.
The different functions of DBMS are
1. Concurrency: concurrent access (meaning 'at the same time') to the same database by multiple users
2. Security: determine access rights of users by rules for security
3. Backup and recovery: processes to back-up the data regularly and recover data if a problem occurs
4. Integrity: database structure and rules improve the integrity of the data
5. Data descriptions: a data encyclopedia stores a description of the data