9.Database Administration

Database administration:-
Database administration is a complex, often thankless chore. The collection of links on this page will help you keep your DBMS humming along at peak performance.
It consists of technical aspect creating and running the database. The basic task is performance monitoring, backup and recovery and assigning and controlling security. Database administrations are trained in detail to installing, configuring and operating the DBMS.

Database administrator (DBA)
A DBA is a complex software package. Installing, running and upgrading a DBMS are not trivial task. Even with personal computer based system, this task can be required the service of fulltime person. Every data requires the service of a DBA which position is generally staff who is trained in the administration of the particular DBMS.
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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. A DBA is usually expected to have experience with one or more of the major database management products, such as Structured Query Language, SAP, and Oracle-based database management software.

DBA task
o Install & upgrade DBMS
o Create user account and monitor security
o Manage backup and recovery of the database
o Monitor and the tune the database performance
o Co-ordinate with DBMS vender and plan for changes
o Maintains DBMS- specific information’s for developer

General tasks
Installation, configuration, upgrade, and migration
Although system administrators are generally responsible for the hardware and operating system on a given server, installation of the database software is typically up to the DBA. This job role requires knowledge of the hardware prerequisites for an efficient database server, and communicating those requirements to the system administrator.

Backup and recovery
DBAs are responsible for developing, implementing, and periodically testing a backup and recovery plan for the databases they manage. Even in large shops where a separate system administrator performs server backups, the DBA has final responsibility for making sure that the backups are being done as scheduled and that they include all the files needed to make database recovery possible after a failure. When failures do occur, the DBA needs to know how to use the backups to return the database to operational status as quickly as possible, without losing any transactions that were committed. There are several ways the database can fail, and the DBA must have a strategy to recover from each. From a business standpoint, there is a cost to doing backups, and the DBA makes management aware of the cost/risk trade-offs of various backup methods.

Database security
Because databases centralize the storage of data, they are attractive targets for hackers and even curious employees. The DBA must understand the particular security model that the database product uses and how to use it effectively to control access to the data. The three basic security tasks are authentication (setting up user accounts to control log-ins to the database), authorization (setting permissions on various parts of the database), and auditing (tracking who did what with the database). The auditing task is particularly important currently, as regulatory laws like Sarbanes-Oxley and HIPAA have reporting requirements that must be met.

Storage and capacity planning
The primary purpose of a database is to store and retrieve data, so planning how much disk storage will be required and monitoring available disk space are key DBA responsibilities. Watching growth trends are important so that the DBA can advise management on long-term capacity plans.

Performance monitoring and tuning
The DBA is responsible for monitoring the database server on a regular basis to identify bottlenecks (parts of the system that are slowing down processing) and remedy them. Tuning a database server is done on multiple levels. The capacity of the server hardware and the way the operating system is configured can become limiting factors, as can the database software configuration. The way the database is physically laid out on the disk drives and the types of indexing chosen also have an effect. The way queries against the database are coded can dramatically change how fast results are returned. A DBA needs to understand which monitoring tools are available at each of these levels and how to use them to tune the system. Proactive tuning is an attitude of designing performance into an application from the start, rather than waiting for problems to occur and fixing them. It requires working closely with developers of applications that run against the database to make sure that best practices are followed so good performance will result.

Troubleshooting
When things do go wrong with the database server, the DBA needs to know how to quickly ascertain the problem and to correct it without losing data or making the situation worse.

Data task by development
Whichever development methodology you follow, certain database task are requires at each step. Most of the tasks are performed by the applications developer, with co-ordinate on with DBA.
a. Data planning-:
It this stage you will have to make a estimate of the data storage requirements. This may helps to decide hardwire requirement of parallel processing number of forms and reports needed etc.

b. Database design
The basic goals of the design stage are to identify the user needs and design the appropriate data tables. Data normalization is the primary database related activity in this state. The final table definition will also provide better estimates of the storage requirement.

c. Data implementations
Define standard for application programming. Development of the application and user interface is the major step. Determine the overall looks and feels of application programming standard and testing procedure are defined.

d. Database operation and maintains
Once the database is place in operation the DBA performs most of the management task. The primary tasks are
a. monitor usage & security
b. performs backup and recovery
c. support the users


Backup and recovery system
Perhaps most critical database management task is backup. No matter how well you plan, no matter how sophisticated your security system. Something well go wrong. Database manager and developer have an obligation to plan for disasters. The most critical aspect of planning to make sure that a current copy of database is easily accessible. Any types of disasters like fire, flood, terrorist attack, power failure computer virus, disk drive crash or accidental deletion required backup data. If there is a problem the database has to be restored from the backup.
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DBAs are responsible for developing, implementing, and periodically testing a backup and recovery plan for the databases they manage. Even in large shops where a separate system administrator performs server backups, the DBA has final responsibility for making sure that the backups are being done as scheduled and that they include all the files needed to make database recovery possible after a failure. When failures do occur, the DBA needs to know how to use the backups to return the database to operational status as quickly as possible, without losing any transactions that were committed. There are several ways the database can fail, and the DBA must have a strategy to recover from each. From a business standpoint, there is a cost to doing backups, and the DBA makes management aware of the cost/risk trade-offs of various backup methods.

Security and privacy issue of database
Computer security is an issue with every company today and any computer application files security problem. The purpose of database is to share data. In a security context you want to control who can share the data and what user can do with it. There are basic categories computer securities.

• Physical security:-
It is the concerned with physical protecting the computing resources and preparing for avoiding physical disaster that might damage equipment or data. The must important task is to make sure that you always have current backup.

• Logical security:-
It consists of protecting the data and controlling access to the data. The essence of logical security is that you want to allow each user to have some access to the data but you want to control exactly what types of access the user will have.