The Plan That Changed Twice This Month
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
A subscription streaming service is building a warehouse to measure churn and downgrade rates and content engagement, and it needs to reconstruct exactly which plan any subscriber was on at any past date even when someone starts, downgrades, and cancels all inside the same billing period, so each of those changes has to survive as its own timestamped record. Viewing has to be analyzed on its own, including ad-break exposure for the ad-supported tier, and churn and downgrades must be sliceable by the channel a subscriber was acquired through and the month they signed up. When a subscriber asks to be forgotten, their personal details must be removable while the historical viewing and subscription records stay intact under a stable, non-identifying key.
Summary
Subscribers come, go, downgrade, and share. The schema has to keep up.
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