Database implementors, who build DBMS software; end users, who wish to store and use data in a DBMS
Database application programmers develop packages that facilitate data access for end users, who are usually not computer professionals, suing the host or data languages and software tools that DBMS vendors provide
Database administrator is responsible for:
Design of the conceptual and physical schemas: interacting with the users of the system to understand what data is to be stored in the DBM and how it is likely to be used
Security and authorization: ensuring that unauthorized data access is not permitted
Data availability and recovery from failures: ensuring if the system fails, users can continue to access as much of the uncorrupted data as possible
Database tuning: modifying the database to ensure adequate performance as user requirements change.