What are the functions and responsibilities of Database Administrator regarding database management ?

The Database Administrator has following responsibilities: Installing and Configuration of Database: DBA is responsible for installing the database software. He configure the software of database and then upgrades it if needed. There are many database software like oracle, Microsoft SQL and MySQL in the industry so DBA decides how the installing and configuring of these database software will take place. Definition of the schema, the architecture of the three levels of the data abstraction, data independence. Modification of the defined schema as and when required. Definition of the storage structure i.e. access method of the data stored in sequential, or indexed or direct. The DBA can be responsible for granting authorization such as creating new used-id, password etc., and also creating the access permissions that each user can or cannot enjoy. DBA is responsible to create user roles, which are collection of the permissions (like read, write etc.) granted and restricted for a class of users. Defining the integrity constraints for the database to ensure that the data entered conform to some rules, thereby increasing the reliability of data. Creating a security mechanism to prevent unauthorized access, accidental or intentional handling of data that can cause security threat. Creating backup and recovery policy. This is essential because in case of a failure the database must be able to revive itself to its complete functionality with no loss of data, as if the failure has never occurred. Tuning Database Performance: Database performance plays an important role for any business. If user is not able to fetch data speedily then it may loss company business. So by tuning a modifying SQL commands a DBA can improves the performance of database. Managing Capacity Issues: All the databases have their limits of storing data in it and the physical memory also has some limitations. DBA has to decide the limit and capacity of database and all the issues related to it.