16. Transactions and Concurrency

This module gives you practical patterns for correctness under high write concurrency.

Lessons

• ACID and Transaction Control
• Isolation Levels and Locking
• Deadlocks and Retry Patterns

Concurrency Risk Table

Risk	Typical fix
Dirty/incorrect reads	Appropriate isolation level
Lost updates	Row locking and optimistic checks
Deadlocks	Consistent lock order + retries

What's Next

• Continue to 17. User Management and Security