Top 50 DBMS Viva Questions and Answers
DBMS viva exams typically test conceptual clarity rather than pure memorization. Below is a preview of high-frequency viva questions along with crisp answers you can use for quick revision.
Fundamental Concepts
Q1. What is DBMS?
Software that enables creation, storage, retrieval, and management of data in databases.
Software that enables creation, storage, retrieval, and management of data in databases.
Q2. What is a database?
An organized collection of related data stored electronically.
An organized collection of related data stored electronically.
Q3. What is a primary key?
A unique identifier for each record in a table; it cannot contain NULL values.
A unique identifier for each record in a table; it cannot contain NULL values.
Q4. What is a candidate key?
Any column or set of columns that can qualify as a unique identifier for a row.
Any column or set of columns that can qualify as a unique identifier for a row.
Q5. What is normalization and why is it used?
A process to organize data and reduce redundancy by dividing large tables into smaller, related tables.
A process to organize data and reduce redundancy by dividing large tables into smaller, related tables.
Keys and Relationships
Q6. What is a foreign key?
A field that links to the primary key of another table, establishing a relationship.
A field that links to the primary key of another table, establishing a relationship.
Q7. What is a composite key?
A primary key made up of two or more columns combined.
A primary key made up of two or more columns combined.
Q8. What is referential integrity?
A rule ensuring foreign key values always match an existing primary key value.
A rule ensuring foreign key values always match an existing primary key value.
Transactions and Concurrency
Q9. What are ACID properties?
Atomicity, Consistency, Isolation, and Durability — four guarantees for reliable transactions.
Atomicity, Consistency, Isolation, and Durability — four guarantees for reliable transactions.
Q10. What is deadlock?
A situation where two or more transactions wait indefinitely for resources locked by each other.
A situation where two or more transactions wait indefinitely for resources locked by each other.
Q11. What is a transaction?
A logical unit of work made up of one or more database operations, executed as a single unit.
A logical unit of work made up of one or more database operations, executed as a single unit.
SQL Basics
Q12. What is the difference between DELETE and TRUNCATE?
DELETE removes rows one at a time and can be rolled back; TRUNCATE removes all rows instantly and resets identity counters.
DELETE removes rows one at a time and can be rolled back; TRUNCATE removes all rows instantly and resets identity counters.
Q13. What is a join?
An SQL operation used to combine rows from two or more tables based on a related column.
An SQL operation used to combine rows from two or more tables based on a related column.
Q14. What is an ER diagram?
A visual representation of entities, attributes, and relationships used during database design.
A visual representation of entities, attributes, and relationships used during database design.
Q15. What is denormalization?
Intentionally introducing redundancy into a normalized database to improve read performance.
Intentionally introducing redundancy into a normalized database to improve read performance.
This preview covers the most repeated viva questions — the full set of 50 (with follow-up questions examiners commonly ask) is available inside the course material.
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