Database代写:CS420 Database Schema

根据题目要求,代写完成四个场景下的数据库设计,包含E-R图,关系图以及UML图。

Problem 1

Consider the following database schema:

  • Supplier(SName, ItemName, Price): supplier SName sells item ItemName at Price
  • Customer(CName, Address): customer CName lives at Address.
  • Order(CName, SName, ItemName, Qty): customer CName has ordered Qty of item ItemName from supplierSName.
  • Item(ItemName, Description): information about items. Every item is supplied by some supplier.

a. Draw the E-R diagram from which the above schema might have been derived. Specify the keys.
b. Show how this ER diagram can be translated to the relational model.
c. Draw the UML diagram.

Problem 2

Your local community library has books, CDs, tapes, and so forth, which are lent to library patrons. The latter have accounts, addresses, and so forth. If a loaned item is overdue, it accumulates penalty. Some patrons are minors, so they must have sponsoring patrons who are responsible for paying penalties (or replacing a book in case of a loss).

a. Use the E-R approach to design a database system for your library.
b. Show how this ER diagram can be translated to the relational model.
c. Use the UML approach to design a database system for your library.

Problem 3

A real estate firm keeps track of the houses for sale and customers looking to buy houses. A house for sale can be listed with this firm or with a different one. Being “listed” with a firm means that the house owner has a contract with an agent who works for that firm. Each house on the market has price, address, owner, and a list of features, such as the number of bedrooms, bathrooms, type of heating, appliances, size of garage, and the like. This list can be different for different houses, and some features can be present in some houses but missing in others. Likewise, each customer has preferences that are expressed in the same terms (the number of bedrooms, bathrooms, etc.). Apart from these preferences, customers specify the price range of houses they are interested in. Perform conceptual design for this enterprise.

a. Use the E-R approach to design a database system for the firm.
b. Show how this ER diagram can be translated to the relational model.
c. Use the UML approach to design a database system for the firm.

Problem 4

A supermarket chain is interested in building a decision support system with which they can analyze the sales of different products in different supermarkets at different times. Each supermarket is in a city, which is in a state, which is in a region. Time can be measured in days, months, quarters, and years. Products have names and categories (produce, canned goods, etc.).
a. Design an E-R diagram for this application.
b. Show how this ER diagram can be translated to the relational model.
c. Use the UML approach to design a database system for the supermarket.

Submit 1 PDF file with the responses to all the problems in order (1,2,3,4).