Questions and answers
What is a DBMS?
Software that stores, retrieves and manages data in databases, for example MySQL, Oracle, PostgreSQL.
What is the difference between DBMS and RDBMS?
An RDBMS stores data in related tables and enforces relationships with keys; a general DBMS need not.
What is a primary key?
A column or set of columns that uniquely identifies each row and cannot be null.
What is a foreign key?
A column that refers to the primary key of another table and enforces referential integrity.
What is the difference between a candidate key and a super key?
A super key is any set of attributes that uniquely identifies rows. A candidate key is a minimal super key.
What is normalization?
The process of organising tables to reduce redundancy and avoid insert, update and delete anomalies.
Explain 1NF, 2NF and 3NF.
1NF: atomic values, no repeating groups. 2NF: 1NF and no partial dependency on part of a composite key. 3NF: 2NF and no transitive dependency.
What is BCNF?
A stricter 3NF in which every determinant is a candidate key.
What are DDL, DML, DCL and TCL?
DDL defines structure (CREATE, ALTER, DROP). DML handles data (INSERT, UPDATE, DELETE, SELECT). DCL controls access (GRANT, REVOKE). TCL manages transactions (COMMIT, ROLLBACK, SAVEPOINT).
What is the difference between DELETE, TRUNCATE and DROP?
DELETE removes selected rows and can be rolled back. TRUNCATE removes all rows quickly. DROP removes the table itself.
What are the types of joins?
Inner join, left outer join, right outer join, full outer join, cross join and self join.
What is the difference between WHERE and HAVING?
WHERE filters rows before grouping; HAVING filters groups after GROUP BY.
What is a view?
A virtual table defined by a stored query.
What is an index?
A data structure that speeds up searches on a column at the cost of extra storage and slower writes.
What are ACID properties?
Atomicity, Consistency, Isolation and Durability: the guarantees of a reliable transaction.
What is a transaction?
A sequence of operations treated as a single unit that either completes fully or not at all.
What is a trigger?
A stored program that runs automatically on INSERT, UPDATE or DELETE on a table.
What is a stored procedure?
A precompiled set of SQL statements stored in the database and called by name.
What is an ER diagram?
A diagram of entities, their attributes and the relationships between them, used to design a database.
What is SQL injection and how do you prevent it?
An attack in which user input changes the SQL query. Prevent it with parameterised queries or prepared statements and input validation.
Questions on your project's database
- How many tables are there and what are their primary keys?
- Show one one-to-many relationship in your ER diagram
- In which normal form is your database and why?
- Write the query behind one report in your project
- How are passwords stored?
FAQs
Is this useful for MSBTE Database Management System (DMS 313302)?
Yes. It matches the oral topics of the K-scheme DBMS course in the third semester.
Last reviewed: 2026-10-11. Always follow the format your own department gives you.