AutoMigrate

AutoMigrate is a feature implemented by several object-relational mappers (ORMs) and database tools that automatically updates the database schema to match the application's data models. It typically runs during application startup or deployment, inspecting model definitions and applying necessary changes to the underlying database.

How it works: The tool compares the current database schema to the model definitions, then issues data definition language statements to create missing tables, add new columns, or create appropriate indexes and constraints. It is often non-destructive by default, focusing on additions rather than dropping or altering existing columns, though some implementations support more extensive changes.

Benefits and use cases: AutoMigrate reduces manual migration scripting, speeds initial development, and helps keep the live schema aligned with code. It can be convenient in small projects or development environments where schema changes are frequent and controlled.

Limitations and caveats: Automatic migrations can cause data loss if destructive changes are performed, may produce downtime or locking during schema updates, and may not handle complex refactorings, such as changing data types, renaming columns, or restructuring tables. It is generally recommended to use explicit, versioned migrations for production systems and to run AutoMigrate only with proper backups and in staged environments.

Examples and variants: The term AutoMigrate is strongly associated with the Go ecosystem’s GORM, but other frameworks offer similar functionality under different names. It is configurable, sometimes with options to disable on startup or to run only in development mode.