Glossary · Phase 7 · Software engineering
Expand and contract
Changing a database in safe steps: add the new shape, move code and data over, and remove the old shape last.
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.
- schema migration: A numbered, one-way script that changes a database's tables, applied in order to every copy of the database.
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