DBMS Users | Database Management System

DBMS Users | Database Management System

DBMS Users : Typically there are three types of users for a DBMS. They are:

  1. The End User who uses the application. Ultimately, this is the user who actually puts the data in the System into use in business. This user need not know anything about the organization of data in the physical level. They also need not be aware of the complete data in the system. They needs to have access and knowledge of only the data she is using.
  2. The Application Programmer who develops the application programs. They has more knowledge about the data and its Structure since she has manipulate the data using her programs. They also need not have access and knowledge of the complete data in the System.
  3. The Database Administrator (DBA) who is like the Super-user of the system. The role of the DBA is very important and is defined by the following functions:

DBA Functions

Defining the Schema

The DBA defines the Schema which contains the structure of the data in the application. The DBA determines what data needs to be present in the system and how this data has to be represented and organized.

Liaising with Users

The DBA needs to interact continuously with the users to understand the data in the system and its use.

Defining Security & integrity Checks

The DBA finds about the access restrictions to be defined and defines security checks accordingly. Data integrity checks are also defined by the DBA.

Defining Backup / Recovery Procedures

The DBA also defines procedures for backup and recovery. Defining backup procedures includes specifying what data is to backed up, the periodicity of taking backups and also the medium and storage place for the backup data.

Monitoring Performance

The DBA has to continuously monitor the performance of the queries and take measures to optimize all the queries in the application.

Other Functions of DBA

Deciding and Loading the Database Contents: The DBA in Consultation with senior management is normally responsible for defining the conceptual schema of the database. The DBA would also be responsible for making changes to the conceptual Schema of the database if and when necessary.

Assisting and Approving Applications and Access: The DBA would normally provide assistance to end-users interested in writing application programs to access the database. The DBA would also approve or disapprove access to the various parts of the database by different users.

Deciding Data Structures: Once the database contents have been decided, the DBA would normally make decisions regarding how data is to be stored and what indexes need to be maintained. In addition, a DBA normally monitors the performance of the DBMS and makes changes to data structures if the performance justifies them. In some cases, radical changes to the data structures may be called for.

 

Backup and Recovery : Since the database is such a valuable asset, the DBA must make all the efforts possible to ensure that the asset is not damaged or lost. This normally requires a DBA to ensure that regular backups of a database are carried out and in case of failure (or Some other disaster like fire or flood), suitable recovery procedures are used to bring the database up with as little down time as possible.

Monitor Actual Usage : The DBA monitors actual usage to ensure that policies laid down regarding use of the database are being followed. The usage information is also used for performance tuning.