The Database Architect Teaches His Nephew: Where the Real Interview Happens

Same uncle, this time in "Database Architect" mode. Same nephew, this time asking the question every backend developer eventually asks out loud.

Part 0: Why Does Every Backend Interview Circle Back to the Database?

A backend developer is judged by how they handle code. A senior backend developer is judged by how they handle data — because data is the one thing in your system that doesn't forgive carelessness. Code with a bug can be redeployed in five minutes. Data corrupted by a bad migration might be gone forever. That asymmetry is the entire reason this topic gets so much interview weight, and it's the entire reason we're spending today on it properly, piece by piece.

Part 1: SQL vs NoSQL — Stop Picking a Religion, Start Picking a Tool

SQL (PostgreSQL, MySQL)