JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD MCA 2018 DATABASE MANAGEMENT SYSTEMS Previous Question Paper (January - 2018 - R13)
Part A is compulsory which carries 20 marks. Answer all questions in Part A. Part B consists of 5 Units. Answer any one full question from each unit.
Part A
Give history of database systems.
Answer
The history of database systems began in the 1960s with File Processing Systems, which suffered from data redundancy and inconsistency. This led to the development of the Hierarchical and Network models (e.g., IBM's IMS) in the late 1960s. In 1970, E.F. Codd introduced the Relational Model, which revolutionized the field by using tables. The 1980s saw the dominance of Relational Database Management Systems (RDBMS) and the standardization of SQL. Modern developments include Object-Oriented, Distributed, and NoSQL databases designed to handle big data and unstructured information.
Explain set operations in relational algebra.
Answer
Set operations in relational algebra operate on two relations that must be union-compatible (same number of attributes with compatible domains). The primary operations are:
- Union (∪): Combines all tuples from both relations, removing duplicates.
- Intersection (∩): Returns only the tuples present in both relations.
- Set Difference (−): Returns tuples present in the first relation but not in the second.
What is normalization? What are useful normal forms?
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Explain about 2PL, serializability and recoverability.
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Distinguish between primary and secondary indices.
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Part B
Describe class hierarchies in ER model.
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Give a brief note on database languages.
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What is a foreign key constraint? Why are such constraints important? What is referential integrity? Give examples.
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What is DBA? Write DBA responsibilities.
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Explain various types of joins with examples.
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Explain logical connectives with examples.
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Consider the following schema: Suppliers(sid, sname, address), Parts(pid, pname, color), Catalog(sid, pid, cost). Write queries in relational algebra, tuple relational calculus, and domain relational calculus for: a) Find names of suppliers who supply red part. b) Find sids of suppliers who supply red or green part. c) Find sids of suppliers who supply red part or at 221 Packer Ave. d) Find sids of suppliers who supply red and green part.
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Consider a relation R with attributes ABCDE. FDs: A->BC, BC->E, E->DA. Consider relation S with FDs: A->BC, B->E, E->DA. Evaluate R and S for BCNF, 4NF, and 5NF.
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Consider relation R(ABCDE). FDs: A->B, BC->E, ED->A. List keys, check for 3NF and BCNF.
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Explain about inclusion dependencies.
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Discuss about transaction support in SQL.
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Explain about recovering from a crash recovery.
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Write some anomalies associated with interleaved execution.
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Write a brief note on ARIES.
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Give comparison of three file organizations in detail.
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Distinguish between extendable and linear hashing.
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Explain levels of redundancy.
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