Database Management System MCQs with Answers
Practice important Database Management System MCQs with answers and explanations.
Chapter: 18
Q281:
In equi-join, the output relation will have:
A. Only non-matching rows from both tables
B. Only matching rows from both tables
C. Matching rows with common attributes appearing once
D. Matching rows with common attributes appearing twice
Correct Answer:
C
Chapter: 18
Q282:
What does a natural join do with common attributes between two relations?
A. Repeats them twice
B. Removes them completely
C. Includes them only once
D. Includes them as NULL
Correct Answer:
D
Chapter: 18
Q283:
What type of join will always include all rows from the right relation?
A. Left Outer Join
B. Right Outer Join
C. Full Outer Join
D. Cross Join
Correct Answer:
B
Chapter: 18
Q284:
In a left outer join, tuples of the left relation with no match in the right relation will have:
A. Null values in the right relation attributes
B. Matching values in the right relation attributes
C. Empty rows in the output
D. Non-matching attributes from the left relation
Correct Answer:
A
Chapter: 18
Q285:
In tuple-oriented relational calculus, what is primarily used to find relation tuples?
A. Predicate variables
B. Domain variables
C. Tuple variables
D. Attribute variables
Correct Answer:
C
Chapter: 18
Q286:
Normalization is a process performed on:
A. Database tables only
B. Conceptual database design only
C. Logical database design only
D. Each table of the database
Correct Answer:
D
Chapter: 18
Q287:
What does relational calculus focus on?
A. How to retrieve data
B. What data should be retrieved
C. How to create tables
D. How to perform joins
Correct Answer:
B
Chapter: 18
Q288:
What is the main objective of normalization?
A. To place the database in the highest form of normalization
B. To remove all redundancy from the database
C. To combine all tables into one
D. To create backup copies of the database
Correct Answer:
A
Chapter: 18
Q289:
In the normalization process, if a table fulfills the requirements of the second form, it is said to be in:
A. First Normal Form
B. Second Normal Form
C. Third Normal Form
D. Fourth Normal Form
Correct Answer:
B
Chapter: 18
Q290:
Which type of join is similar to equi-join but removes duplicate common attributes?
A. Natural Join
B. Theta Join
C. Semi Join
D. Left Outer Join
Correct Answer:
A
Chapter: 18
Q291:
In the right outer join, tuples from the right relation with no match in the left relation will have:
A. Null values in the left relation attributes
B. Matching values in the left relation attributes
C. Empty rows in the output
D. Non-matching attributes from the right relation
Correct Answer:
A
Chapter: 18
Q292:
Fill in the blank: In a theta join, the cross product is performed on __________ rows of one relation.
A. all selected
B. all available
C. no matching
D. some selected
Correct Answer:
A
Chapter: 18
Q293:
Which form of relational calculus involves specifying what data should be retrieved?
A. Tuple Oriented
B. Domain Oriented
C. Procedural
D. Declarative
Correct Answer:
B
Chapter: 18
Q294:
The result of a semi join will include attributes from:
A. The second relation only
B. The first relation only
C. Both relations equally
D. None of the relations
Correct Answer:
B
Chapter: 18
Q295:
In an outer join, tuples that do not match in both relations are left as:
A. NULL values in both relations
B. Empty rows in the output
C. NULL values in one relation
D. Non-matching attributes in both relations
Correct Answer:
C
Chapter: 18
Q296:
What is the Cartesian product used for in joins?
A. To combine all rows from both relations
B. To apply selection criteria before joining
C. To ensure uniqueness of common attributes
D. To filter rows based on a condition
Correct Answer:
A
Chapter: 19
Q297:
What is the concept on which normalization is based?
A. Functional Dependency
B. Entity Relationship
C. Data Redundancy
D. Data Integrity
Correct Answer:
A
Chapter: 19
Q298:
If A functionally determines B, what does this mean?
A. B can be calculated from A
B. A and B are always equal
C. Each value of A has exactly one corresponding value of B
D. A causes B
Correct Answer:
C
Chapter: 19
Q299:
What is a determinant in a functional dependency?
A. The attribute on the right side of the arrow
B. The attribute on the left side of the arrow
C. The value that can be calculated from another
D. A set of attributes not involved in functional dependency
Correct Answer:
B
Chapter: 19
Q300:
A super key is a set of attributes that:
A. Can be used to uniquely identify an entity
B. Identifies multiple rows in a table
C. Is only used for indexing
D. Does not affect the uniqueness of rows
Correct Answer:
A