Write each of the following dependencies as an FD:
This exercise asks you to converting business statements into dependencies. Consider the following relation DiskDrive(serialNumber, manufacturer, model, batch, capacity, retailer). Each tuple in the relation DiskDrive contains information about a disk drive with a unique serialNumber, made by a manufacturer, with a particular model, released in a certain batch, which has a certain storage capacity, and is sold by a certain retailer. For example, the tuple DiskDrive(1978619, WesternDigital, A2235X, 765234, 500, CompUSA) specifies that WesternDigital made a disk drive with serial number 1978619, model number A2235X in batch 765235 with 500GB that is sold by CompUSA.
a. The manufacturer and serial number uniquely identifies the drive
b. A model number is registered by a manufacturer and hence can’t be used by another manufacturer.
c. All disk drives in a particular batch are the same model.
d. All disk drives of a particular model of a particular manufacturer have exactly the same capacity.
a. manufacturer, serialNumber ? model, batch, capacity, retailer
b. model ? manufacturer
c. manufacturer, batch ? model
d. model ? capacity (Comment: 10.35.d can be “model, manufacturer ? capacity.” There is nothing in the question that suggests we should “optimize” our FDs by assuming the other requirements)
You might also like to view...
Windows does not include troubleshooting for networks.
Answer the following statement true (T) or false (F)
An aerial shot is a shot that shows a subject from an angle rather than straight on.
Answer the following statement true (T) or false (F)
In rebutting assertions made by Zacharias Moussaoui's defense counsel, an expert witness noted that the FBI uses three methods of _______ a hard drive: Linuxdd, SafeBack, and Logicube
a. Erasing b. Encrypting c. Duplicating d. None of the above
List the three parts of a class definition.
What will be an ideal response?