Question 1: Why do we need virtual databases?

Answer: Consider a person viewing a list of the musical concert events in one web page. Suppose he wishes to find the cheapest way to attend a concert from his hometowm. He has to copy the data from that page(dates and cities) into other web pages where he can find airfares to those cities on those dates. In fact, he may have to enter the same data into many different pages(for different airlines), along with additional data, such as his hometown. He then has to read and keep track of the best combination of city, date, flight and price.

Consider the case of job hunting on the web. In order to make a meaningful career choice, a job seeker needs information on available opportunities and other related data. Information about job openings is scattered across thousands of different websites-company home pages and newspaper calssifieds sites.

The solution to both these problems is to convert these different data sources into a single virtual database. This data integration in virtual databases allows users to acquire information from different databases and heterogeneous or distributed computer systems. Thus virtual databases are required in key domains such as Employment Classifieds, Consumer Shopping, Real estate, etc.

Question 2: What are the advantages of a virtual databse?

Answer: The advantages of the virtual database are:
-Allows easy integration of various data to get the desired information: Virtual databases provide updated information by integrating data on a need basis.

-Utilizes real time data for real time decision making: Users can obtain real time information instantaneously.

-Reduces time and cost for system development: Data integration in virtual databses allows users to reduce the time and cost for system building as well as providing a flexible system development environment.

-Reduces the effort in management of conventional databases.

-A highly flexible,understandable data saving organisation that has the capability of any development can be created.

Sai Janaki Tejaswi P
-1MS07IS087