The Plan That Changed Twice This Month

A medium Data Modeling interview practice problem on DataDriven. Write and execute real data modeling code with instant grading.

Domain

Data Modeling

Difficulty

medium

Seniority

L5

Problem

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.

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