What does "migration" mean in Programming?

Question

I'm learning Ruby on Rails and it talk about how Migration changes the state of the database by using the command bundle exec rake db:migrate, but what exactly does that mean?

Answer 1

Migrations are a way of defining the schema of your database. Rails provides an API for adding/dropping/modifying database columns and tables using Ruby code. These files are knows as migrations. Here is a link to the documentation: http://edgeguides.rubyonrails.org/active_record_migrations.html, but migrations are not a concept unique to Rails. For example, Django also uses migrations to manage the state of the database. The short answer is that migrations are a code-based way to manage the structure, or schema of your database.