The relation shown in Figure 15.12 describes hospitals (hospitalName) that require certain items (itemDescription), which are supplied by suppliers (supplierNo) to the hospitals (hospitalName). Furthermore, whenever a hospital (h) requires a certain item (i) and a supplier (s) supplies that item (i) and the supplier (s) already supplies at least one item to that hospital (h), then the supplier (s) will also be supplying the required item (i) to the hospital (h). In this example, assume that a description of an item (itemDescription) uniquely identifies each type of item.
(a) Describe why the relation shown in Figure 15.12 is not in 5NF.
(b) Describe and illustrate the process of normalizing the relation shown in Figure 15.12 to 5NF.
a. This relation has a join dependency JD(hospitalName, itemDescription, supplierNo) among the three projections: R1(hospitalName, itemDescription), R2(hospitalName, supplierNo), and R3(itemDescription, supplierNo) of HospitalItemSupplier.
b. To remove the join dependency, we create the following 5NF relations:
HospitalItem(hospitalName, itemDescription)
HospitalSupplier(hospitalName, supplierNo)
ItemSupplier(itemDescription, supplierNo)
You might also like to view...
Many of the HTML codes used to format tables in HTML4 are now considered to be ____________________, or no longer within the current standard and in danger of becoming obsolete.
Fill in the blank(s) with the appropriate word(s).
In Calc, landscape orientation is the default when printing a worksheet
Indicate whether the statement is true or false
Details that describe an Excel file, such as the author or title, are called the document ________
A) references B) labels C) values D) properties
You are trying to connect to your switch via the console port and are having trouble connecting to the switch. You check the setting for your terminal emulation program and find the following:
Port COM1 Baud Rate 300 Data 8 Parity None Stop 1 Flow Control None Which setting is incorrect, and what should it be set to? A) Port: com2 B) Baud Rate: 9600 C) Parity: 1 D) Flow Control: Xon/Xoff