MCA-2103
2015/-I/O2
M.C.A. DEGREE EXAMINATION
Second Year-First Semester
DATA BASE MANAGEMENT SYSTEMS
(Effective from the admitted batch of 2000-2001)
Time: Three Hours
Maximum: 75 Marks
First question is compulsory.
Answer any four from the remaining questions.
All questions carry equal marks.
Write all bits of the - first question at one place.
1. (a) Define Super key, Primary key and Candidate key.
(b) What is the difference between a strong and weak entity set ? What type of integrity constraint a weak entity set represents.
(c) When two objects in an object oriented database are said to be equal ? Explain how does it differ from the concept of tuple equality in relational data base.
(d) Why most database systems require schedule to be recoverable ?
If a schedule is recoverable does it imply that it is free of cascading rollback ? Justify your answer with examples.
(e) Users are permitted to pass authorization to other. This may lead to user having access rights for which they are not really authorized. How is this problem tackled in DBMS ?
2. (a) Identify the basic features of an object in an object oriented data model.
(b) Compare inheritance in the EER model and that, of in the 00 model
3. (a) Given E-R diagram of an enterprise briefly explain how an appropriate relational scheme can be designed. Clearly explain how the tables corresponding to different types of entities and relations can constructed and how integrity constraints will be handled. Illustrate the steps with appropriate examples.
(b) What is meant by a recursive relationship type ? Give some examples of recursive relationship types.
4. (a) Explain security in QBE.
(b) Give an algorithm to test the I serializability of schedule.
5. (a) What is meant by closure of a set of functional dependencies ?
(b) What non-trivial functional dependencies hold in the following relation ?
| A
| B
| C
| D
|
| 0
| 0
| 0
| 1
|
| 2
| 1
| 2
| 0
|
| 1
| 1
| 2
| 0
|
| 0
| 0
| 1
| 2
|
6. (a) Describe the recovery technique that employs the immediate update scheme.
(b) Indicate how the recovery scheme works in a single user environment if the system fails
* After the transaction starts and before the read.
* After the read and before the write.
* After the write and before the commit.
* After the commit and before all database, entries are flushed onto disk.
7. (a) Describe a multiversion concurrency control protocol based on time stamps and show that it is safe.
(b) Define a Transaction and list of acid properties.
8. The following is a relational data base Customer (Cname, Cstreet, Ccity) Account (bname, acno, balance) Depositor (Cname, acno) Loan (bnam e, lbanno, amount) Borrower (Cname, loanno) Branch (bname, bcity, assets)
Express the following in relational algebra and in SQL:
(a) Find the customer who live in "Hyderabad".
(b) Find all customer who have an account but not a loan.
(c) Find the largest account balance in the bank.
(d) Find the names of all branches with customer who have an account in the bank and who live in "Hyderabad".
(e) Find all customers who have an account at all branches located in "Madras".
