Constraints as Code
CHECK, UNIQUE, and FK constraints — why database-level constraints beat application-level validation every time.
Think of database constraints like the guardrails on a mountain road. You could drive the road without them — most of the time, you'd be fine. But the one time you drift too close to the edge at 2 AM in a rainstorm, those guardrails are the difference between a minor scare and driving off a cliff.
Database constraints work the same way. They're rules encoded directly into your schema that prevent bad data from ever being stored. Not "usually prevent." Not "prevent if the application remembers to check." Always prevent. No matter what application, script, admin tool, or AI agent writes to the database, the constraints hold.
This is the most important lesson in database design: the database is the last line of defense for your data, and constraints are how you arm it.
The Cons
This lesson is part of the Guild Member curriculum. Plans start at $29/mo.