Comparison of RDBMS and NoSQL

---

1. Introduction

Relational Database Management Systems (RDBMS) store data in tables with fixed schema, whereas NoSQL databases store data in non-relational formats such as documents, key-value pairs, columns, or graphs.

Both systems are used depending on application requirements.

---

2. Key Differences Between RDBMS and NoSQL

Aspect	RDBMS	NoSQL
Data Model	Tables (rows & columns)	Key-Value, Document, Column, Graph
Schema	Fixed schema	Flexible / Schema-less
Data Structure	Structured data	Structured, semi-structured, unstructured
Scalability	Vertical (scale-up)	Horizontal (scale-out)
Consistency Model	Strong consistency (ACID)	Eventual consistency (BASE)
Transactions	Fully ACID compliant	Limited or relaxed transactions
Query Language	SQL	No single standard query language
Joins	Supported	Limited or not supported
Performance	Good for complex queries	High performance for large data
Availability	Moderate	High availability
Cost	Higher (licenses, hardware)	Often open-source, cost-effective

---

3. Advantages of RDBMS

• Strong data consistency

• Supports complex transactions

• Mature and stable technology

• Powerful SQL queries

• Suitable for structured data

---

4. Advantages of NoSQL

• Handles large volumes of data

• High scalability and availability

• Flexible schema

• Suitable for distributed systems

• Better performance for big data and real-time applications

---

5. When to Use RDBMS

RDBMS is preferred when:

• Data structure is fixed

• Transactions are critical

• Strong consistency is required

• Data relationships are complex

Examples:
Banking systems, payroll, inventory management

---

6. When to Use NoSQL

NoSQL is preferred when:

• Data is large and rapidly growing

• Schema changes frequently

• High availability is needed

• Application is distributed

Examples:
Social networks, e-commerce, analytics, IoT applications