Glossary · Phase 7 · Software engineering
Schema migration
A numbered, one-way script that changes a database's tables, applied in order to every copy of the database.
Try it now
Each step is a separate deploy, so old and new code can run side by side while servers update one by one.
Learn it properly
Changing a database safely · Numbered migrations in transactions, required columns and backfills, and expand-and-contract changes. About 40 minutes.
Other terms from the same lesson
- backfill: Filling in a new column's values for rows that existed before the column was added.
- expand and contract: Changing a database in safe steps: add the new shape, move code and data over, and remove the old shape last.
Never trained an AI?
Teach a small one to write, right in your browser. It takes about 20 seconds and needs no account.