Design a polymorphic comments system

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

Domain

Data Modeling

Difficulty

medium

Problem

Design a polymorphic comments system. Instead of separate comment tables per entity, create one comments table that can reference either posts or photos using a commentable_type and commentable_id pattern.

Practice This Problem

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