What are the DBMS functions?

DBMS provides the following functions:

Concurrency: 
      Concurrent access (meaning 'at the same time') to the same database by multiple users

Security: 
      Security rules to determine access rights of users

Backup and recovery: 
      Processes to back-up the data regularly and recover data if a problem occurs

Integrity: 
      Database structure and rules improve the integrity of the data

Data descriptions: 
      A data dictionary provides a description of the data