The Person They Were Then

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

Domain

Data Modeling

Difficulty

easy

Seniority

mid

Problem

We run a messaging app where a user's subscription tier and country both drift over time, and the ad-revenue team needs every past impression to reflect the tier and country the user actually had the moment it fired. Design the schema that lets analysts slice historical ad revenue by the profile state as of each event.

Practice This Problem

Solve this Data Modeling problem with real code execution. DataDriven runs your solution and grades it automatically.