Wednesday, March 11, 2009

Database Tips

A database is a collection of related data stored in an efficient and compact manner. The word “efficient” means that stored data can be accessed very easily and quickly.
Similarly, the word “compact” means that stored data takes up as little space as possible. In the above definition of database, the phrase “related data’ is used. It means that a database contains data or information about a particular topic such as:
  • Database of employees that contains data of employees of an organization or department.
  • Database of students that contains data of students of college or university.

A database holds related data as well as description of that data. For this reason, a database is also defined as a self describing collection of integrated records. The description of data is known as the system catalog or data dictionary or metadata. For example when a table of a database is designed, the data type, size, format and other descriptions of fields are specified. This is an example of metadata, which describes the properties of data to be stored into fields of table.

The data of any organization is its integral part. The data is very important for developing new products and their marketing. The data must be accurate and available when needed. This is the reason that all organization must organize and manage their data into database. The databases are used for variety of purposes in as organization. For example, when you purchase goods from your local supermarket, the checkout assistant will pass the purchased product through a scanner device known as bar code reader. This device will read the bar code printed on the product and gives the accurate price of the item. Actually, the bar code reader is accessing the database, which contains the information about the products. The bar code reader is linked to a database application program, which uses the bar code to access price of item. The database program automatically updates the database. The assistant can also check whether a required item is in stock by running the database application program. Similarly, you can purchase goods using your credit card. Your credit is checked by a card reader linked to a computer system. In this case, there is a database somewhere that contains information about your credit. Almost all organizations and government departments of every country in world use database to maintain their records. Some examples of large databases that have been developed around the world are:

  • When you draw amount from bank through ATM card, you are accessing the database; your account is accessed and checked through auto teller machine. When you draw some amount from your account, your record in the database is automatically updated immediately.

  • When you visit your local library, there may be a computerized database containing details of the books in the library. There will be a computerized index, which allows you to find a book based on its title, its author’s name etc.

  • The meteorological organization contains databases having information about current and previous meteorological data. The meteorological department is totally dependent on the meteorological data.

A database may be generated and maintained manually or it may be computerized. The library card catalog is an example of a database that is created and maintained manually. On the other hand, a computerized database may be created and maintained either by using application program, which is developed specifically for that purpose or by a database management systems.