Draw a ERD (Entity–relationship model). Only need ERD including entity and connection. project is in below:

Sweeping Bulldog (SB) is an online textbook exchange portal. It allows an individual or customer (student, faculty, staff, etc.) to sell their used textbooks directly to other people.

An individual or customer may be a student, a faculty member, a staff member, or any other people on and off UMD campus. If the individual is a UMD student, need major information. If the individual is a professor, the department name needs to be recorded.

An individual may have two different roles at SB, a seller or a buyer. When an individual sells an item, the name, description, asking price which is the price that the seller desires, notification price which is the price at which the seller should be notified. If the item is a book, the ISBN number and author information needs to be kept.

To keep the status of the item in transaction, SB often needs to update the status with ‘In-process’, ’Pending’, ‘Sold’, and ‘Shipped’. When a seller places an item, the status is ‘In-process’ SB also needs to keep a history record of selling activities, which basically includes seller’s identification number.

To better manage customers, SB needs to keep track of their email addresses so that any successful transaction will be notified. SB also needs to create a password for a customer together with account information so that he can log in later.

When a customer wants to buy an item, they can place a bid on that item. This bid must be higher than any previous bid prices for the same item. There are some generally rules about the new biding price, i.e., 10% more of the previous price if the previous price is no more than $50, and 5% more if the previous price is more than $50. The information required for bidding includes an automatic identification.

A seller of an item can review the various bids that have been made on that item. When the seller finds an acceptable bid, they can accept that bid. The sale process involves recording information about the winning bid as a sale and notifying the buyer who places that bid. A bid is ‘pending’ until the bidder acknowledges the purchase of the item. For the sale information, the item information, buyer information, winning price, completion date need to be kept.

If a buyer is off campus or from other colleges, SB needs to record their shipping addresses, if the address is not the same as that in the individual information. SB will handle the shipping issues and usually ships a book after the buyer sends in a check.

Warehouse pickers are responsible for packaging the items for each successful bid. They need to know basic customer information (shipping information). No money information should be shown to these pickers. Upon completion of the shipment package the status of the items is upgraded to "shipped" and the shipment is sent out to the member. Because a customer may have several successful bids, several sold items can be put together on a single shipment ticket Corresponding item information needs to be printed on a shipping ticket.

SB also sells old items by themselves. SB collects these old items from some small distributors. SB maintains information about the distributors themselves. Each distributor has a unique name and address. All the distributors come from three states, i.e., MN, WI, and IA. There is also a primary contact person at each distributor for SB, whose name, and contact phone number form part of the information about distributors. When SB realizes a particular item is in demand, it generates a purchase order for that item and sends it to one of many distributors for that item. The order point for a book cannot be over 20. SB has learnt that it is a lot more efficient to generate a purchase order that covers more than just one item so long as the associated distributor carries all of items in the purchase order. The purchase order information includes order number, order date, a description for each item, and the order quantity for each. A staff from SB would call the distributor to obtain the price quote and availability for each item before forwarding the purchase order. All the distributors for books must be from MN. An expected delivery date (for the entire order, not on an item basis) from the supplier then becomes part of the purchase order information. The expected delivery date must be within 2 weeks after the order date.

Distributors package all of the items in a single purchase order into one shipment when shipping to SB. The three carriers for SB (i.e., FedEx, UPS, USPS) impose some restrictions on packages sizes and weights. Each distributor generates an invoice against each purchase order. The invoice includes the shipment date, items shipped with quantities of each and bottom bidding price. This information is very important for SB to be able to inform their staff members at the time of receiving orders.