What is a migration in EF Core?

A migration is a versioned description of changes needed to move a database schema from one model state to another.

When the EF Core model changes, a migration can contain operations such as creating tables, adding columns, creating indexes, changing constraints, or dropping objects. Migrations also maintain model metadata so EF Core can determine future differences.

Migrations should be reviewed before production deployment because generated schema changes can have performance, compatibility, and data-loss implications.