Vibe codingMediumvc-g585

Subject Ai prompt specLevel Mid–Senior~18 minCommon in Algorithms & data structures interviewsIndustries Software development, Technology

Question

You want an AI agent to write a database schema change that adds a NOT NULL column with a backfilled default to a large, actively-written Postgres table, plus the migration to deploy it with zero downtime. Write the spec. What does a casual 'add a NOT NULL column with a default' prompt get wrong on a big live table?

What a strong answer looks like

Treat the AI’s output as a draft to verify, not an answer to trust. Name the specific flaw and the input that triggers it, say how you’d catch it — tests, edge cases, reading critically — and how you’d re-prompt or decompose to get it right.

Learn the concepts

Describe your solution

Vibe coding: describe the solution in plain language (or narrate it) and the coach grades your approach. Generating runnable code from your description is coming next.

Run or narrate your approach, then ask the coach.