1. Using these data, investigate possible functional dependencies among the columns of data. Justify your assumptions on the basis of these sample data and also on the basis of what you know about retail sales.

List 5 possible functional dependencies from the sample sales data:

List 5 possible functional dependencies from the sample purchase data:

2. Given your assumptions in part A, comment on the appropriateness of the following designs (are they good or not and why?):

1. CUSTOMER (LastName, FirstName, Phone, EmailAddress, InvoiceDate, InvoiceItem, Price, Tax, Total)

2. CUSTOMER (LastName, FirstName, Phone, EmailAddress, InvoiceDate, InvoiceItem, Price, Tax, Total)

3. CUSTOMER (LastName, FirstName, Phone, EmailAddress, InvoiceDate, InvoiceItem, Price, Tax, Total

4. CUSTOMER (LastName, FirstName, Phone, EmailAddress, InvoiceDate, InvoiceItem, Price, Tax, Total

5. CUSTOMER (LastName, FirstName, Phone, EmailAddress, InvoiceDate, InvoiceItem, Price, Tax, Tota

6. CUSTOMER (LastName, FirstName, Phone, EmailAddress)

and:

SALE (InvoiceDate, InvoiceItem, Price, Tax, Total)

7. CUSTOMER (LastName, FirstName, Phone, EmailAddress, InvoiceDate)

and:

SALE (InvoiceDate, InvoiceItem, Price, Tax, Total)

8. CUSTOMER (LastName, FirstName, Phone, EmailAddress, InvoiceDate, InvoiceItem)

and:

SALE (InvoiceDate, InvoiceItem, Price, Tax, Total)

3. Modify what you consider to be the best design in part B to include surrogate ID columns called CustomerID and SaleID. How does this improve the design?

The resulting Tables are: