# A producer team has filed three proposed schema changes for the orders event: rename amount to amoun Canonical URL: Domain: Pipeline Design ยท Difficulty: medium ## Problem A producer team has filed three proposed schema changes for the orders event: rename amount to amount_cents, add an optional refund_reason field with default null, and remove the deprecated legacy_sku field. The section's classification is direct: adding an optional field with a default is additive (safe), renaming or removing fields downstream code reads is destructive (forces coordinated deploy), and the safe path for a rename is the expand-contract pattern under the hood. On the canvas, classify each proposed change by adding three classification nodes downstream of the producer, one per change, whose names state which class the change belongs to (additive, destructive, or coordinated rename via expand-contract). ## Related - [All practice problems](https://datadriven.io/problems) - [Mock interview mode](https://datadriven.io/interview/a-producer-team-has-filed-three-proposed-schema-changes-for-d8722650) - [System Design Interview Questions](https://datadriven.io/data-engineering-system-design) - [Data Engineering Interview Prep Guide](https://datadriven.io/data-engineer-interview-prep) - [Daily Challenge](https://datadriven.io/daily) --- Source: DataDriven (https://datadriven.io). 100% free data engineering interview prep. Live code execution against Postgres 16, Python 3.11, and Spark sandboxes. No paywall, no premium tier, no signup gate.