01. Introduction to Databases in AWS

A database is a structured way to store, organize, and retrieve data efficiently. Unlike file storage (EBS, EFS, S3), databases allow for:

• Indexing and querying
• Relationships between datasets
• Efficient searching and transactions

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✌️ Types of Databases

🧩 01. Relational Databases (SQL)

Structured data stored in tables (like Excel sheets) with relations between them.

Features:

• Predefined schema (columns, rows)
• Relationships (foreign keys)
• Query using SQL (Structured Query Language)
• Linked with another table: a

Student Table:

StudentID	DeptID	Name	Email
101	10	John Doe	john@school.edu
102	20	Jane Roe	jane@school.edu

Examples:

• MySQL, PostgreSQL, Oracle, SQL Server, MariaDB

Use Cases:

• Transactional applications
• Financial systems
• Enterprise data storage

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🚀 02. NoSQL Databases (Non-Relational)

Flexible schema designed for fast, scalable, and distributed data storage.

Key Benefits:

Benefit	Description
Flexibility	Schema can evolve easily
Scalability	Scales horizontally across servers
High Performance	Optimized for specific data models
Functionality	Built for modern app requirements

Types:

• Key-Value (e.g., DynamoDB), Document (e.g., MongoDB, DocumentDB), Graph, In-memory, Search databases

Example Data (JSON):

{
  "name": "Abc",
  "age": 30,
  "cars": ["Ford", "BMW", "Fiat"],
  "address": {
    "type": "house",
    "number": 23,
    "street": "Abc Road"
  }
}

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🧰 Use Cases:

• Real-time applications
• IoT and mobile systems
• Social, recommendation, and analytics platforms

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Benefits of Managed Databases on AWS

• ⚙️ Quick provisioning
• 💾 Built-in high availability
• 📈 Vertical & horizontal scaling
• 🔁 Automated backup & restore
• 🧩 No OS patching required
• 📊 Integrated monitoring & alerting

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✅ Summary

Database Type	Structure	Schema	Scalability	Use Case
SQL	Relational	Fixed	Vertical	Traditional, Transactional Apps
NoSQL	Non-Relational	Flexible	Horizontal	Modern, Real-Time, Scalable Apps