Question :1

You should present an entity-relationship diagram describing your design

We begin by describing some of the requirements of the database and explain the deliverables for this part of the project. What follows is a description of the types of information that must be stored and how it will be accessed. The requirements are patterned after (but not identical to) the ebay on-line auction web site (www.ebay.com). It may help to explore that site to better understand these requirements.

Items - The focus here is the items put up for auction. The items can be pretty much everything. We assign an identifier to an item when it is put up for auction. This is used to identify the item. The seller provides a short description (no more than 500 characters) of the item and categorizes it as described below. The seller can also specify a URL to provide a more detailed description. The seller is entitled to specify a reserve amount. At the end of the auction, if no bid is higher than the reserve, the seller is not required to sell the item. The seller must also specify the location of the item (i.e., the State it would be shipped from).

Categories When a seller puts up an item up for auction, they must categorize it using a predefined classification tree. Each node represents a set of items. The root of the tree is labeled All represents all items. Each node has on average ten children. Each has a descriptive name and represent some subset of the items represented by the parent. An item is described by specifying one path through this classification tree. For example, we may categorize an item as: Computers:Hardware:PC Systems; or Computers:Hardware:Portable The depth of the tree varies but is never more than ten levels deep.

Registered Users To sell or bid on an item a user must be registered. A registered user is identified by a user name and authenticated with a password. In addition, we request the following information. 1. E-mail address 2. Name 3. Address 4. Phone number 5. Type of credit card / Credit Card Number / Expiration Date 6. Age 7. Gender 8. Annual Income Of course the last three items are collected solely for telemarketers, but we wont tell the users that. We attempt to control fraud by allowing users to comment on the past behavior of other users. A user that took part in an auction can register a Positive, Neutral, or Negative evaluation of the seller. These ratings and a short explanation (less than 500 characters) are then made available to other users. In this way, a users reputation is forced to precede him.

Bidding A user can place one or more bids on an item as long as they are not the seller of the item. (We will implement simple bidding rather than the proxy bidding used on ebay). Each bid that is placed must be $5 larger than all previous bids and must be placed before the auction ends. At the end of the auction the seller and all bidders are notified of the high bid and the user that placed it. Contact information is sent to the seller and high bidder so that they can complete the transaction. An auction starts when the seller registered the item for auction and ends exactly two weeks later. Information about an auction in which the item is not sold can be discarded immediately.

Delivery After a winner is determined, the difficult part of an auction begins. The seller does not want to deliver the item until he has been paid, and the buyer does not want to pay until the item has been delivered. We will serve as a trusted third party to resolve the standoff. After a winner in the auction has been announced, the seller will ship the item to us. When and if the item is received, we place a charge on the credit card the user supplied us with. If the charge is successful, we forward the item to the buyer and mail a check to the seller. If the item does not arrive in two weeks, or the charge does not go through, we declare the auction void and if necessary, return the item. Information about auctions that are successful will be maintained in the system for at least six months. Information about successful and voided delivery cannot be discarded until six months after we have sent e-mail to all parties notifying them on the outcome. We will not wait for acknowledgements, as they may never arrive. To support the removal of this information, you should keep track of when notifications where sent.

Reports to Telemarketers Periodically we produce a report including the name, address, e-mail, phone, age, gender and annual income to a telemarketing firm. Browsing Users are able to browse the auction items by traversing the category tree. At each point, they are given a summary of all the items that appear in that category.

Browsing Users are able to browse the auction items by traversing the category

tree. At each point, they are given a summary of all the items that appear in that

category.