DBMS | 2022
Answer the following questions in comments So, that everybody can see the Answers!
Section A (5×2=10)
1. Differentiate between explicit and implicit cursor.
2. Define various types of relationship with suitable example.
3. Mention the properties of transactions.
4. How is serializability ensured in database
5. Solve the following query
Student(Id,Name,Section, Department) Result(Subject_code,Subject_name, Marks)
Retrieve the list of students who have scored more than 75 marks in DBMS subject.
Section B (4 x 5=20)
6. Explain the significance of data Independence in databases? Illustrate the role of logical data independence and physical data independence with examples.
8. Given the relational schema:
ENROLL (SW, C#, Section), Si is student number.
TEACH (Prof, C#, Section), C# is course number.
ADVISE (Prof, S#), Prof is Thesis advisor of S#
PRE-REQ (C#, pre-C), pre-c is prerequisite course,
STUDENT (S#, Sname), Sname is student name.
GRADE (S#, C#, grade, year)
Give queries expressed in SQL
(i) List of students taking courses with smith or jones.
(ii) List all students taking at least one course that
(iii) List those professors who teach more than one their advisor teaches section of the same course.
(iv) List all students number and course number
(v) List the student number and course number who got grade A
9. Elucidate the terms primary key, candidate key, Super key, Foreign key and alternate key with suitable examples related to database
10. (a) State the importance of lossless join property of a FDs: ABC, CD, B-E decomposition?
(b) Find the Super Keys: R(ABCDE)
Section C (3 x 10 =30)
11. Elaborate the three levels of architecture of CO2 database using suitable diagram? (6) (b) Differentiate between Derived Attributes and multivalued attributes with example.
12. Design an E-R diagram upto level 1 DFD for a car- insurance company whose customers own one or more cars each. Each car has associated with it zero to any number of recorded accidents.
13. (a) Describe the recovery method of update deferred.
(b) Which of these means that the concurrent execution of transactions is equivalent to the case where the transactions executed serially in some arbitrary order?