A DataBase Management System, often known as a DBMS, is a piece of software installed on a computer to manage, store, retrieve, and update data. It handles the data, the database engine, as well as the conceptual database schema to make the organizing and manipulation of data easier. It thus acts as an interface between the customer and the database and helps to alter the data format, column names, document structure, as well as file structure itself.

Basic Level

Q1. What are the different types of normalization in DBMS, and explain them?

There are four types of normalization in DBMS: 1NF, 2NF, 3NF, and BCNF (Boyce-Codd Normal Form).

• 1NF: A relation is in First Normal Form (1NF) when each table cell contains only atomic values—meaning each attribute must have a single value or NULL. The goal is to eliminate duplicate columns from tables.
• 2NF: A relation is in Second Normal Form (2NF) when it is in 1NF and has no partial dependencies between relationships.
• 3NF: A relation is in Third Normal Form (3NF) when it meets two conditions: 1) It is already in 2NF, and 2) It has no transitive dependencies for non-prime attributes. A transitive dependency (A → B) exists when A is not a super key and B is a non-prime attribute.
• BCNF (Boyce-Codd Normal Form): A relation is in BCNF when it meets two conditions: 1) It is already in 3NF, and 2) For all non-trivial functional dependencies "A → B", A must be a super key of the relation.

Q2. What is RDBMS? Differentiate between RDBMS and DBMS.

It stands for Relational Database Management System (RDBMS). It is a database system that accesses data through relationships between tables using standard fields. The main difference between RDBMS and DBMS is that DBMS stores data in files, while RDBMS stores data in tables.

Q3. What is the difference between the DROP command, TRUNCATE command, and DELETE command?

TRUNCATE and DROP commands are DDL commands used to delete database tables. Once executed, these actions cannot be rolled back, so they should be used with caution. When using DROP or TRUNCATE, all related table indexes are also deleted. In contrast, DELETE is a DML command used to remove specific rows or columns from a table, and these changes can be rolled back.

Q4. What is an Entity, Entity Type, and Entity Set in DBMS?

1. Entity is an object or concept that exists independently and can be uniquely identified.

2. Entity Type is the classification or category that defines a group of similar entities.

3. Entity Setis a collection of all entities belonging to the same entity type at a given point in time.

Q5. What are the advantages of DBMS over traditional File-based Systems?

• Enhanced data security with controlled access