COSC 61 Review Questions and Answers Graded A+
1) The identifier of the entity becomes the ________ of the corresponding table.
A) primary key
B) foreign key
C) supertype
D) subtype - Answers a
2) The ideal primary key is ________.
A) short
B) numeric
C) fixed
D) A and B
E) A, B, and C -...
1) The identifier of the entity becomes the ________ of the corresponding table.
A) primary key
B) foreign key
C) supertype
D) subtype - Answers a
2) The ideal primary key is ________.
A) short
B) numeric
C) fixed
D) A and B
E) A, B, and C - Answers e
3) A surrogate key should be considered when ________.
A) a relationship is M:N
B) a composite key is required
C) the key contains a lengthy text field
D) the key contains a number
E) an index needs to be created - Answers c
4) Which of the following is not true about surrogate keys?
A) They are identifiers that are supplied by the system, not the users.
B) They have no meaning to the users.
C) They are non-unique within a table.
D) They can be problematic when combining databases.
E) The DBMS will not allow their values to be changed. - Answers c
5) One of the important properties of a column is whether or not it is ________.
, A) found in more than one entity
B) required
C) character or numeric
D) subject to normalization
E) subject to denormalization - Answers b
6) In a relational database design, all relationships are expressed by ________.
A) creating a primary key
B) creating a foreign key
C) creating a supertype
D) creating a subtype
E) creating a line between entities - Answers b
7) Which of the following would be a reason to denormalize a relation?
A) Relax security
B) Lack of design time
C) End user preference
D) Improve performance
E) None of the above - Answers d
8) Which of the following is true about representing a weak entity with the relational model?
A) If the weak entity is existence-dependent, the key of the parent must be part of the key of the weak
entity.
B) If the strong entity has a minimum cardinality of 1, the key of the weak entity must be part of the
strong entity.
C) If the weak entity is ID-dependent, the key of the weak entity must be part of the key of the parent
entity.
D) If the weak entity is ID-dependent, the key of the parent entity must be part of the key of the weak
entity.
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller TutorJosh. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £6.47. You're not tied to anything after your purchase.
