UNIT - V

 
5.      DBA (Database Administration) 
Database management is among the fundamental processes in the software field of computing. Databases are used in almost every enterprise and the bigger the enterprise is, the bigger and more complicated the databases will have to be. Although facilitated to the greatest extent possible by database management system solutions, it still needs continuous human intervention. And while a system administrator can, in most cases, take care of the database, there are a lot of times when a specialist is needed, someone dedicated to database management.

Database administrator (DBA)

The people responsible for managing databases are called database administrators. A database administrator (DBA) directs or performs all activities related to maintaining a successful database environment.

Responsibilities include designing, implementing, and maintaining the database system; establishing policies and procedures pertaining to the management, security, maintenance, and use of the database management system; and training employees in database management and use.
 
The DBA position is generally staffed by a specialist who is trained in the administration of a particular DBMS. 

Role of DBA
A database administrator's responsibilities can include the following tasks: 

·         Installing and upgrading the database server and application tools
·         Allocating system storage and planning future storage requirements for the database system
·         Creating primary database storage structures (table spaces) after application developers  have designed an application
·         Creating primary objects (tables, views, indexes) once application developers have designed an application
·         Modifying the database structure, as necessary, from information given by   application developers
·         Enrolling users and maintaining system security
·         Ensuring compliance with database vendor license agreement
·         Controlling and monitoring user access to the database
·         Monitoring and optimizing the performance of the database
·         Planning for backup and recovery of database information
·         Maintaining archived data on tape
·         Backing up and restoring the database
·         Contacting database vendor for technical support
 

5.1.  Database tasks by development stages

The tasks of a database are performed by the application developers.
Ø  Data base planning
Ø  Database design
Ø  Database implementation
Ø  Database operation &maintenances 

Database Planning
o   The first step is to estimate the data storage requirements.
o   There initial estimates helps to determine the size and capacity of the hardware needed to support the application.
o   The initial investigation should also provide some idea of the number of forms and reports that will be needed, as well as their complexity.
o   These numbers will be used to estimate the time and cost required to develop the system. 

Database Design
·         The goal of design stage is to identify the user needs and design the appropriate data tables.
·         Team work coordination &project management are important administrative task at this stage.
·         Team work is supported with data standards as defined by the DA.
·         Communication is enhanced through a shared data repository, networked tools, E-mail, Computer aided software engineering (CASE) tools.
·         The project is often split by assigning forms and reports to individual team members.
·         Each person is then responsible for identifying the business assumptions and defining the normalized tables needed for the assigned forms. 

Database Implementation
Developments of the application & user interface are the major steps in database implementation. 

·         Standards for application programming
o   User interface must be carefully chosen.
o   Programming structure and test procedures help ensures compatibility of the components and provide quality control.
o   Programming variable &objects.
o  Test procedure.

·         Data access and ownership
·         Loading database
·         Backup and recovery have to be created and tested. Backups are handled in two forms: full back up at predefined checkpoints and complete backups to provide safer recovery.
·         Complete backup are easier to restore and provide safer recovery.
·         Training programs have to be created for operators and users.


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