Rails can work without it, what does
schema.rb really do?
It documents the final current state of the database schema. Often, especially when you have more than a couple of migrations, it’s hard to deduct the schema just from the migrations alone. With a present
schema.rb, you can just have a look there. ActiveRecord itself will indeed not use it. It will introspect the database during runtime as this is much safer than to expect users to keep the
schema.rb up-to-date. However to avoid confusion of your developers, you should always maintain a file that is up-to-date with your migrations.
Use “br annotate” to update the comments of tables’ columns in each model file.