JNTU Exam Papers
1. (a) What is outer join ? What are its advantages over natural join ? Give an example.
(b) What is a domain constraint? Explain with an example.
2. (a) Discuss the various DDL, DML commands with illustrations in SQL.
(b) Why are null values not preferred in a relation? [12+4]
3. (a) What is the difference between a file organisation and an access method
(b) Why is accessing a disk block expensive. Discuss the time components involved in accessing a disk block.
4. Discuss the implementation of a select operation. Explain the processing mechanism by means of an example.
5. Show that the following equivalences hold and explain how they can be applied to improve the efficiency of certain updates.
(a) (r1 [ r2) [ r3 = r1 [ (r2 [ r3)
(b) r1 [ r2 = r2 = r2 [ r3(c)?p(r1 ? r2) = ?p(r1) ? ?p(r2)
6. (a) Construct an E-R diagram for university registrar’s office. The office maintains data about each class, including the instructor, the enrollment and the time and place of the class meetings. For each student class pair, a grade is recorded. Determine the entities and relationships that exist between the entities. Also construct the tabular representation of the entities and relationships.
(b) What is an entity type? What is an entityset? Explain the difference between the entity, entity type and entityset?
7. (a) Explain Binary locks, Shared Locks and Exclusive locks ?
(b) What is the two phase locking protocal? How does is guarantee serializability.
8. Explain in detail the ARIES recovery method.