2013-2015 Oracle Academy English Database Design - Student MID TEST EXAM ANSWER PART 2

Section 6
	(Answer all questions in this section)
		31.	As a database designer, you do not need to worry about where in the datamodel you store a particular attribute; as long as you get it onto the ERD, your job is done. True or False?		Mark for Review (1) Points
			True
			False
		32.	Would it be a good idea to model age as an attribute of STUDENT?		Mark for Review (1) Points
			Yes
			Yes, it would prevent our having to calculate someone's age every time we need it.
			Sometimes, but not all of the time
			No - it breaks the Normalization rules
		33.	Normalizing an Entity to 1st Normal Form is done by removing any attributes that contain muliple values. True or False?		Mark for Review (1) Points
			True
			False
		34.	People are not born with "numbers", but a lot of systems assign student numbers, customer IDs, etc. ﾠA shoe has a color, a size, a style, but may not have a descriptive "number". So, to be able to uniquely and efficiently identify one instance of the entity SHOE, a/an ______________ UID can be created.		Mark for Review (1) Points
			Artificial
			Unrealistic
			Structured
			Identification
		35.	A unique identifier must be made up of more than one attribute. True or False?		Mark for Review (1) Points
			True
			False
	Section 7
	(Answer all questions in this section)
		36.	Arcs are used to visually represent _________ between two or more relationships in an ERD.		Mark for Review (1) Points
			Sameness
			Differences
			Exclusivity
			Inheritance
		37.	An arc can also be modeled as Supertype and Subtypes. True or False?		Mark for Review (1) Points
			True
			False
		38.	Which of the following is NOT a relationship type?		Mark for Review (1) Points
			Some to None
			One to One
			One to Many
			Many to Many
		39.	Primary UIDs are:		Mark for Review (1) Points
			Something that each Entity should have, but is not mandatory
			Useful as an alternative means of identifying instances of an entity, independent of their datatype
			Mandatory in data modeling
			Always comprised of numbers
		40.	No parts of an UID are mandatory. True or False?		Mark for Review (1) Points
			True
			False Section 7 (Answer all questions in this section) 41.  Historical data must never be kept. True or False?  Mark for Review (1) Points True False 42.  A particular problem may be solved using either a Recursive Relationship or a Hierarchical Relationship, though not at the same time. True or False?  Mark for Review (1) Points True False Section 9 (Answer all questions in this section) 43.  You are doing a data model for a computer sales company where the price of postage depends upon the day of the week that goods are shipped. So shipping is more expensive if the customer wants a delivery to take place on a Saturday or Sunday. What would be the best way to model this?  Mark for Review (1) Points Use a Delivery Day entity, which holds prices against week days, and ensure the we also have an attribute for the Requested Delivery Day in the Order Entity. Email current prices to all employees whenever a price changes. Update the prices in the system, print out the current prices when they change, and pin them on the company noticeboard. Allow them to enter whatever delivery charge they want. 44.  All systems must include functionality to provide logging or journaling in conceptual data models. True or False?  Mark for Review (1) Points True False 45.  What do users lose when using a system that has no concept of time?  Mark for Review (1) Points Journalling becomes much easier. Journalling becomes slightly harder. Tracking data over a period of time becomes impossible. Nothing is lost if a system does not track time. 46.  When you add the concept of time to your data model, your model becomes more complex. True or False?  Mark for Review (1) Points True False Section 10 (Answer all questions in this section) 47.  There is no point in trying to group your entities together on your diagram according to volume, and making a diagram look nice is a waste of time. True or False?  Mark for Review (1) Points True False 48.  Formal rules do exist for drawing ERD's. Even though they are only guidelines, you should always try to follow them. True or False?  Mark for Review (1) Points True False 49.  A datamodel containing generic modeling techniques must not be mixed in with non-generic models. The generic entities MUST be drawn on a diagram of their own. True or False?  Mark for Review (1) Points True False 50.  Generic models are generally far more complex than a specific model. True or False?  Mark for Review (1) Points True False