The Endless Thread
A medium Data Modeling mock interview question on DataDriven, with an AI interviewer who asks follow-up questions and a hire or no-hire decision at the end.
- Domain
- Data Modeling
- Difficulty
- medium
- Seniority
- L5
Interview Prompt
Dashboards for a photo-and-video social network keep showing the same account following one creator twice and the same user liking one post twice, so the engagement team wants a warehouse model where a follow is identified by exactly who follows whom and a like by exactly which user liked which post, making either duplicate impossible to store without any application checks. Users create posts that are each a photo or a video, follow one another one direction at a time, and like posts, while a comment either sits on a post or replies to another comment. Design the model so the product team can report engagement per content type.
Summary
Follows, likes, replies to replies. It never stops.
How This Interview Works
- Read the vague prompt (just like a real interview)
- Ask clarifying questions to the AI interviewer
- Draw your data model on the schema canvas: tables, keys and relationships
- Answer the interviewer's follow-up questions, then get a hire or no-hire decision