Question 1

Q.1. (a) What is DBMS? How are data stored in DBMS? Explain. [8]

Accepted Answer

A DBMS is a software system that defines, stores, manipulates, and controls access to structured data, hiding physical storage details from applications; internally it organizes data into files, pages, and blocks on secondary storage using structures such as heap, sorted, and hashed files, and it brings well-known advantages (redundancy control, consistency, integrity, concurrency, security, recovery, standardized SQL access) at the cost of higher software/hardware expense, complexity, and some performance overhead compared to plain file processing.

Question 2

Q.1. (a) Explain the distinctions among primary key, candidate key and super …

Accepted Answer

Super keys, candidate keys, and primary keys form a nested hierarchy of uniqueness constraints on a relation - a super key is any attribute set that uniquely identifies tuples, a candidate key is a minimal super key, and the primary key is the one candidate key chosen by the designer as the principal identifier; these ideas are illustrated with a students example and a Venn-style diagram, followed by an E-R diagram for a car-insurance company showing Customer, Car, and Accident entities connected through the Owns and Involved-in relationships with 1:N cardinalities.

Question 3

Q.2. (a) Explain the difference between physical and logical Interdependence.…

Accepted Answer

Physical data independence is the ability to change the internal storage structures without affecting the conceptual schema or application programs, whereas logical data independence is the ability to change the conceptual schema itself without breaking existing external views or applications; both concepts are explained through the three-schema ANSI-SPARC architecture, followed by a description of the four set operators of relational algebra - union, intersection, set difference, and Cartesian product - with notation and examples.

Question 4

Q.2. (a) Explain the following term with suitable examples - (i) Relational m…

Accepted Answer

This answer defines four core relational-database terms - the relational model, natural join, procedural versus non-procedural languages, and the division operator - each illustrated with a short example, and then discusses denormalization as the deliberate, controlled introduction of redundancy into an already normalized schema to speed up read-heavy queries, along with when it is appropriate and its trade-offs.

Question 5

Q.3. (a) What do you mean by nested query. Explain with suitable examples. [8]

Accepted Answer

A nested query is a SQL query that embeds another complete SELECT statement inside its WHERE, HAVING, or FROM clause, and can be classified as single-row or multi-row, and as correlated or non-correlated, illustrated here with an example that finds employees earning more than the average salary; this is followed by an explanation of SQL views as virtual, derived tables that simplify complex queries, enforce security, and provide logical data independence.

Question 6

Q.3. (a) What do you mean by JDBC. Explain the process of connectivity with D…

Accepted Answer

JDBC is a standard Java API that lets Java programs connect to and interact with relational databases through a well-defined connectivity process (loading the driver, opening a connection, executing statements, processing the result set, and closing the connection), demonstrated here with a simple code example; the second part explains DDL statements (CREATE, ALTER, DROP) used to define database structure, and DML statements (SELECT, INSERT, UPDATE, DELETE) used to manipulate the actual data, each with example SQL.

Question 7

Q.4. (a) What is Hash File organization? Also explain Hash Index with suitabl…

Accepted Answer

Hash file organization places records into buckets chosen by applying a hash function to a key field, giving fast average-case direct access, and a hash index applies the same hashing idea as an auxiliary structure mapping keys to bucket/record addresses rather than storing the records themselves; this is contrasted with primary indexes, which are sparse and built on the ordering field of a sequential file, versus secondary indexes, which are dense and built on non-ordering fields.

Question 8

Q.4. (a) Describe Static and Dynamic Hashing. [8]

Accepted Answer

Static hashing uses a fixed number of buckets decided at file-creation time and can suffer from overflow as the file grows, whereas dynamic hashing schemes such as extendible hashing grow the bucket structure incrementally to avoid this problem; the second part explains the inverted file structure, which maps each distinct key value to a list of matching record identifiers, and the multi-list structure, which links records together via multiple field-specific linked lists, both illustrated with diagrams.

Question 9

Q.5. (a) What do you understand by Serializability of schedules? Explain with…

Accepted Answer

A schedule of concurrently executing transactions is serializable if its effect is equivalent to some serial execution of the same transactions, and conflict serializability can be tested by building a precedence graph and checking it for cycles, illustrated here with a worked two-transaction example; the second part surveys recovery techniques (deferred-update, immediate-update, checkpointing, and shadow paging) and explains the central role of the transaction log in enabling UNDO and REDO under the write-ahead-logging protocol.

Question 10

Q.5. Write a short note on - (a) Deadlock prevention [4] (b) Two phase lockin…

Accepted Answer

This composite answer covers four core concurrency-and-recovery topics in short-note form: deadlock prevention schemes (wait-die and wound-wait based on transaction timestamps), the two-phase locking protocol with its growing and shrinking phases (and the strict 2PL variant), the four ACID properties (atomicity, consistency, isolation, durability) with examples, and deadlock detection using a wait-for graph with cycle checking and victim selection for recovery.

Data Base Management System