data-migrations-reviewer

Reviewing database migrations for data integrity involves assessing schema changes and data transformations across deploy windows, rollbacks, and backfills to flag irreversible changes and prevent potential data loss.

Checking if schema changes break running code requires verifying references across serializers, APIs, and background jobs to catch deploy-time inconsistencies and ensure cross-reference integrity.

You need to backfill data for NOT NULL columns when adding them to existing tables, ensuring safe defaults are present before the migration applies to prevent deployment-time data integrity failures.

Handling rollbacks for irreversible database migrations requires identifying migrations lacking rollback plans and assessing rollback strategies to avoid permanent data loss from column drops or type changes.

A dual-write strategy matters during schema transitions because it ensures both old and new columns are updated simultaneously, preventing data inconsistencies when migrating between different schema versions.

Preventing partial data migrations requires detecting missing transaction boundaries in multi-step transforms, ensuring all steps complete successfully or roll back together to maintain data integrity.