Logical Database Design(Engineering > Computer Science And Engineering > Database System ) Questions and Answers

Question 1. A transitive dependency is which of the following?
  1.    A functional dependency between two or more key attributes.
  2.    A relation that is in first normal form.
  3.    A relation that is in second normal form.
  4.    A functional dependency between two or more nonkey attributes.
Explanation:-
Answer: Option D. -> A functional dependency between two or more nonkey attributes.
Question 2. A foreign key is which of the following?
  1.    The same thing as a primary key
  2.    An attribute that serves no purpose
  3.    An attribute that serves as the primary key of another relation
  4.    Any attribute
Explanation:-
Answer: Option C. -> An attribute that serves as the primary key of another relation
Question 3. The entity integrity rule states that:
  1.    no primary key attribute may be null.
  2.    no primary key may be equal to a value in a foreign key.
  3.    no primary key may be unique.
  4.    no primary key can be composite.
Explanation:-
Answer: Option A. -> no primary key attribute may be null.
Question 4. If no multivalued attributes exist and no partial dependencies exist in a relation, then the relation is in what normal form?
  1.    First normal form
  2.    Third normal form
  3.    Second normal form
  4.    Fourth normal form
Explanation:-
Answer: Option C. -> Second normal form
Question 5. When mapping a many-to-many unary relationship into a relation which of the following is true?
  1.    Four relations are created.
  2.    Two relations are created.
  3.    Three relations are created.
  4.    One relation is created.
Explanation:-
Answer: Option B. -> Two relations are created.
Question 6. If no multivalued attributes exist in a relation, then the relation is in what normal form?
  1.    Fourth normal form
  2.    Third normal form
  3.    Second normal form
  4.    First normal form
Explanation:-
Answer: Option C. -> Second normal form
Question 7. When mapping a binary many-to-many relationship into a relation which of the following is true?
  1.    Four relations are created.
  2.    Two relations are created.
  3.    Three relations are created.
  4.    One relation is created.
Explanation:-
Answer: Option C. -> Three relations are created.
Question 8. A primary key is which of the following?
  1.    An attribute that uniquely identifies each column
  2.    A derived attribute
  3.    An attribute that uniquely identifies each row
  4.    Any attribute
Explanation:-
Answer: Option C. -> An attribute that uniquely identifies each row
Question 9. When mapping a multivalued attribute into a relation which of the following is true?
  1.    Four relations are created.
  2.    Two relations are created.
  3.    One relation is created.
  4.    Three relations are created.
Explanation:-
Answer: Option B. -> Two relations are created.
Question 10. The relational model consists of:
  1.    data redundancy.
  2.    operations using non-SQL languages.
  3.    data in the form of tables.
  4.    unorganized data.
Explanation:-
Answer: Option C. -> data in the form of tables.
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