Page 15 - DCAP402_DCAO204_DATABASE MANAGEMENT SYSTEM_MANAGING DATABASE

Database Management Systems/Managing Database

Notes
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Case Study Requirements Analysis

T he owner of B&N has thought about what he wants and offers a concise summary:

“I would like my customers to be able to browse my catalog of books and to place orders
over the Internet. Currently, I take orders over the phone. I have mostly corporate
customers who call me and give me the ISBN number of a book and a quantity. I then
prepare a shipment that contains the books they have ordered. If I don’t have enough
copies in stock, I order additional copies and delay the shipment until the new copies
arrive; I want to ship a customer’s entire order together. My catalog includes all the books
that I sell. For each book, the catalog contains its ISBN number, title, author, purchase
price, sales price, and the year the book was published. Most of my customers are regulars,
and I have records with their name, address, and credit card number. New customers have
to call me first and establish an account before they can use my Web site.

On my new Web site, customers should first identify themselves by their unique customer
identification number. Then they should be able to browse my catalog and to place orders
online.”

DBDudes’s consultants are a little surprised by how quickly the requirements phase was
completed it usually takes them weeks of discussions (and many lunches and dinners) to
get this done but return to their offices to analyze this information.

1.7 Summary

 A database is a collection of persistent data that is used by the application system of some
enterprise. The enterprise may be a Bank, a Hospital, an Educational Institution, a Library,
etc.

 The word persistence means once the data of the database is accepted by the DBMS, it can
then be removed from the database only by some explicit request.
 It can not be deleted or modified because of some side effect just like the programming
language variables.

 There are several advantages of storing the data in database rather than storing it in
operating system files. An example, university database, to illustrate this concept was
discussed.
 In the DBMS environment we speak of many people. For example, the main people involved
are DBA, Database Designers, and various types of users.
 Though database approach has few disadvantages under some specific circumstances, the
use of database is indispensable. The major implications of database approach are:

 Potential for enforcing standards
 Reduced application development time
 Flexibility
 Economically viable

 Data integrity and security

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