Page 35 - AIS access_chang_ingraham

PROBLEMS 33

Business situations Cardinalities

Sales Cash collections

1. Cash sales (1,1) (1,1)
2. Installment sales for firms like car dealers;
down payment is required.
3. The company often has credit sales. Customers
must pay full amount for each transaction.

Sales Inventory

4. A regular retail store that sells low-cost, mass-
produced items and often carries new items.
5. A construction company that builds custom
homes only.

2.3 Normalize a wholesale company's database
Given below is the design of a Sales table for a wholesale company. Indicate the primary key for the
table. Given the current design of this table, list two violations of the basic requirements of a relational
data model. Indicate possible anomalies in the table and then normalize the table to third normal form.

SO# Invoice Item Description Quantity Unit Customer# Customer
Date # Ordered Price Name

101 7/5/2006 2033 Washer 5 $359.99 22 Brown Co.
2051 Dryer 8 $372.00
102 7/5/2006 1099 TV 4 $258.00 26 Homebase

103 7/6/2006 2028 VCR 10 $179.99 24 Easy Shop
2034 CD player 10 $185.00
2045 DVD player 5 $200.00

104 7/8/2000 1099 TV 15 $258.00 22 Brown Co.

2.4 Normalize a library's database
Given below is the table of data for a library. First, determine which attribute is the best primary key.
Second, examine the table and indicate the anomalies that may occur with the original design of this
database. Why? Third, nOlmalize the table into the third normal form to prepare it for use in a rela-
tional database environment.

Call# Title Borrower First Name Last Name Date Out Date Due
10# ~.f
K561.02 Soccer S551442 John Austin 12-03-05 01-03-06
D221.67 US Presidents S702361 James Wilson 12-20-05 01-20-06
1264.89 HR Laws & F012618 Mark Ding 12-20-05 03-20-06
Regulations
H122.34 Volcanoes S702361 James Wilson 12-20-05 01-20-06
K249.02 Swimming S002579 Freddie Sunder 01-03-06 02-03-06
M426.52 Egypt S002579 Freddie Sunder 01-03-06 02-03-06
K922.4 Badminton F012618 Mark Ding 01-05-06 04-05-06