Database Management Systems
Mahatma Gandhi Central University, Bihar
B.Tech Computer Science & Engineering
Semester 5 Examination, 2025
Database Management Systems (CSET3134)
Assessment Questions
Database Management Systems (CSET3134) - 2025
Section A (MCQ)
Attempt all questions. Each question carries one mark.
- 1
In a relational database there are three relations: Customers = C(CName), Shops = S(SName), Buys = B(CName, SName). Then the Relational Algebra expression C - ΠCName((C × S) - B) (Π is the projection operator) returns the names of:
- 2
Which of the following is not an integrity constraint?
- 3
Consider the statements: S1: NULL values are allowed in Alternate keys. S2: If a NULL value is present in the Alternate key, then that particular Alternate key cannot be referenced by foreign key. Which of the above statements are true?
- 4
Consider two Transactions T1: R1(A) R1(B) W1(B), and T2: R2(B) R2(A) W2(A). Among all the possible schedules between T1 and T2, if one schedule is selected then what is the probability that the selected schedule is view serializable?
- 5
Consider the statements: S1: A Schedule whose Precedence graph has no edges is always conflict serializable. S2: A Schedule whose Precedence graph has no edges is always view serializable. Which of the statements is/are True?
- 6
If any relation R consists only simple candidate keys, then R will always in:
- 7
If a Relation R having 4 attributes consists only trivial Functional dependencies, then total how many numbers of super keys are possible?
- 8
In RDBMS software, Concurrency Controller is responsible for
- 9
If relation R contains 100 records and relation S contains 75 records then R-S contains maximum ___ records.
- 10
Schedule S: W1(A) W2(A) C2 R1 is:
Section B (Short Answer)
Write briefly in 250 words (Short Answer Questions – 20 Marks). Attempt ANY FOUR questions. Each question carries 5 Marks.
- 1
Find the highest Normal Form for Relation R(A,B,C) with FD {B → C}.
- 2
What do you mean by non-conflict pairs? Explain with the help of suitable example.
- 3
What do you mean by Union compatibility?
- 4
What is Cascading Rollback? Explain with help of suitable example.
- 5
Find the minimal cover for FD set F= {A → C, AC → D, E → AD, E → H}.
- 6
Define Left Outer Join with the help of suitable example.
Section C (Long Answer)
Write in 500 Words (Long Answer Questions – 30 Marks). Attempt ALL questions having internal choices. The question carries 10 marks.
- 1
Answer any ONE of the following
(a)What do you mean by Conflict equality of two schedules? How can you check whether two schedules are conflict equal or not? Check whether schedules S1: R1(A) W1(A) R2(A) R2(B) R1(B) W1(B) and S2: R1(A) W1(A) R2(A) R1(B) R2(B) W1(B) are conflict equal or not.
OR
(b)What is View Serializability? Check whether the schedule S: W1(A) R2(A) W3(A) R4(A) W5(A) R6(A) is view serializable or not and if S is view serializable then find all possible view equal serial schedules.
- 2
Answer any ONE of the following
(a)Explain the keywords IN, ANY, ALL, EXISTS for nested queries that return Empty or Non-Empty sets, with the help of suitable examples.
OR
(b)Write the conditions for a relation to be in 3NF. Prove that every binary relation (relation with two attributes) is always in BCNF.
- 3
Answer any ONE of the following
(a)Consider three relations: Suppliers (sid, sname, rating), Parts (pid, pname, color), and Catalog (sid, pid, price). Assume every part is supplied by at least one supplier and every supplier supplies at least one part.
OR
(b)Write a relational algebra expression to retrieve the Pids of all parts that are supplied by every supplier whose rating is greater than 5.