14. Triggers

Triggers run automatically when changes occur. They are useful for enforcing rules close to the data, but they can also make behavior harder to reason about if overused.

Decision Guide

Need	Prefer	Notes
Audit changes	AFTER trigger	Write to an audit table
Validate data beyond constraints	BEFORE trigger	Prefer constraints when possible
Maintain derived columns (e.g., updated_at)	BEFORE UPDATE trigger	Keep it small and deterministic

Lessons

• Trigger Fundamentals
• Audit and Validation Triggers

What's Next

• Continue to 15. Scheduling and Automation