Data migration is the process of transporting data between computers, storage devices or formats. It is a key consideration for any system implementation, upgrade or consolidation. During data migration, software programs or scripts are used to map system data for automated migration.

In OroCommerce Migrations are a way of defining the schema of your database. OroCommerce provides a bundle for adding/dropping/modifying database columns and tables using PHP code, The OroCommerce Bundle based on Doctrine Migrations project which offer additional functionality on top of the database abstraction layer (DBAL) for versioning your database schema and easily deploying changes to it. It is a very easy to use and a powerful tool.

The migration in OroCommerce divided on 2 type:

Schema Migration:  defining the schema of your database  for adding/dropping/modifying database columns and tables using PHP code.
The command responsible from console is : 
php bin/console oro:migration:load --force --env prod

Data Migration: load a  set of data into a database that can then be used for testing or to help give you some interesting data while you're developing your application. 
The command responsible from console is : 
php bin/console oro:migration:data:load --env prod

See the video the explore how using it: