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rails-db:tldr:5f483
The command rails db:migrate
is used in Ruby on Rails applications to apply database migrations.
Migrations are a way to alter the database schema over time. They define the changes that need to be made to the database structure, such as creating or modifying tables, columns, indexes, etc. They are written in Ruby and follow a specific format.
When you run rails db:migrate
, Rails checks the db/migrate
directory in your application for any pending migration files. It then executes each migration file that hasn't been applied yet, in the order they were created.
The migrations are executed with the help of ActiveRecord, the ORM (Object Relational Mapping) tool provided by Rails. ActiveRecord translates the migration files into appropriate SQL statements to apply the changes to the database schema.
Running rails db:migrate
is a critical step when you are developing a Rails application and need to create or modify database tables and structures. It ensures that your database schema stays in sync with your application code.