Database Concepts Learning Guide

A comprehensive, hands-on guide to database concepts covering everything from fundamentals to advanced topics. Each topic includes detailed lessons, visual diagrams, and practical code examples.

📚 Topics Covered

1. Database Concepts & Models

• Relational vs NoSQL databases
• Data models (tables, documents, key-value, graph)
• Normalization & denormalization
• Polyglot persistence and CAP theorem

2. Data Storage & Access

• Row-oriented vs column-oriented storage
• Storage engines (InnoDB, RocksDB, LSM Trees)
• Page organization and buffer pool management
• Write-Ahead Logging (WAL)

3. Indexing & Query Optimization

• B-Tree, Hash, GiST, GIN indexes
• Covering indexes and composite indexes
• Query execution plans (EXPLAIN ANALYZE)
• Index maintenance and optimization strategies

4. Transactions & Consistency

• ACID properties
• Transaction isolation levels
• Locking mechanisms and deadlock prevention
• MVCC and distributed transactions (2PC, Saga)

5. Replication & High Availability

• Master-slave replication
• Synchronous vs asynchronous replication
• Failover strategies
• Multi-master and leaderless replication

6. Sharding & Partitioning

• Horizontal vs vertical partitioning
• Sharding key selection
• Consistent hashing
• Resharding strategies and hotspot handling

7. Caching & Performance Optimization

• Cache types and strategies
• Cache-aside, write-through, write-behind patterns
• Cache invalidation
• Multi-level caching and cache coherence

8. Backup, Recovery & Data Integrity

• Full, incremental, differential backups
• Point-in-time recovery (PITR)
• Write-Ahead Logging
• Backup automation and testing

9. Security & Compliance

• Authentication and authorization (RBAC)
• Encryption at rest and in transit
• Row-level security (RLS)
• Audit logging and GDPR compliance

10. Operations & Tooling

• Schema migrations (Flyway, Liquibase)
• Monitoring and metrics
• Scaling strategies (vertical/horizontal)
• Zero-downtime deployments
• Disaster recovery drills

🎯 Learning Path

Beginner Track (🟢)

Start with basic concepts in each topic:

1. Database Concepts & Models → Relational basics
2. Data Storage & Access → Row vs column storage
3. Indexing → B-Tree indexes
4. Transactions → ACID properties

Intermediate Track (🟡)

Progress to intermediate concepts:

1. Normalization (1NF-3NF)
2. Page organization and WAL
3. Covering indexes and query plans
4. Isolation levels and locking

Advanced Track (🔴)

Master advanced topics:

1. Polyglot persistence and CAP theorem
2. LSM trees and write amplification
3. Specialized indexes (GiST, GIN)
4. Distributed transactions and MVCC
5. Consistent hashing and resharding
6. Cache coherence and multi-level caching

📖 How to Use This Guide

Each topic directory contains:

lesson.md

• Comprehensive explanations
• Three difficulty levels (🟢 Basic, 🟡 Intermediate, 🔴 Advanced)
• Real-world examples and use cases
• Best practices and anti-patterns

diagram.md

• Visual Mermaid diagrams (dark-themed)
• Architecture diagrams
• Sequence diagrams
• Flowcharts and comparisons

examples/

• Working code examples
• SQL scripts (PostgreSQL)
• Java implementations
• Practical demonstrations

🛠️ Prerequisites

Software Requirements

• PostgreSQL 14+: Primary database for examples
• Java 17+: For Java code examples
• Redis: For caching examples
• MongoDB: For NoSQL examples
• Neo4j: For graph database examples

Installation

PostgreSQL:

# macOS
brew install postgresql@14

# Ubuntu
sudo apt-get install postgresql-14

# Start service
brew services start postgresql@14

Redis:

# macOS
brew install redis
brew services start redis

MongoDB:

# macOS
brew tap mongodb/brew
brew install mongodb-community
brew services start mongodb-community

🚀 Quick Start

1. Clone or download this repository
2. Start with Topic 1: Database Concepts & Models
3. Read lesson.md for theory
4. Review diagram.md for visualizations
5. Run examples to practice
6. Progress sequentially through topics

📊 Progress Tracking

Use the checklist to track your learning:

• Topic 1: Database Concepts & Models
• Topic 2: Data Storage & Access
• Topic 3: Indexing & Query Optimization
• Topic 4: Transactions & Consistency
• Topic 5: Replication & High Availability
• Topic 6: Sharding & Partitioning
• Topic 7: Caching & Performance Optimization
• Topic 8: Backup, Recovery & Data Integrity
• Topic 9: Security & Compliance
• Topic 10: Operations & Tooling

🎓 Learning Objectives

By completing this guide, you will:

• ✅ Understand fundamental database concepts
• ✅ Design efficient database schemas
• ✅ Optimize queries and indexes
• ✅ Implement transactions correctly
• ✅ Set up replication and high availability
• ✅ Shard and partition data effectively
• ✅ Implement caching strategies
• ✅ Secure databases and ensure compliance
• ✅ Operate databases in production

📚 Recommended Reading

• "Designing Data-Intensive Applications" by Martin Kleppmann
• "Database Internals" by Alex Petrov
• "Database Reliability Engineering" by Laine Campbell
• PostgreSQL Documentation: https://www.postgresql.org/docs/
• "Use The Index, Luke!" by Markus Winand

🤝 Contributing

This is a learning resource. If you find errors or have suggestions:

1. Document the issue clearly
2. Provide context and examples
3. Suggest improvements

📝 License

This educational content is provided as-is for learning purposes.

🙏 Acknowledgments

• PostgreSQL Community
• Database research papers and documentation
• Real-world production experiences
• Open-source database tools and projects

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Start Learning: Topic 1: Database Concepts & Models →

Last Updated: 2024-01-21