Schema migrations are essential for safely updating the schema of a relational database, as they allow changes to be applied in a controlled manner without disrupting existing data, in contrast to stateless application code deployments. The process involves using SQL scripts stored in version control to track schema changes over time, which can be applied sequentially to recreate a database's state at any point. A practical example using Drizzle, a type-safe ORM for TypeScript applications, illustrates how to generate and apply schema migrations, including adding a new column to a table in a Postgres database hosted by Neon. By simulating different environments, such as development and production, the article demonstrates how schema migrations keep database schemas synchronized with application code changes. Additionally, automating these migrations with GitHub Actions ensures consistency and reduces the risk of errors during deployment, as it integrates with platforms like Vercel to trigger migrations and deployments simultaneously when changes occur in the main repository branch.