To start the migration, pass makemigrations to manage.py. This argument will start the migration process by inspecting the contents of models.py. All of the Python class data models will be read, and the corresponding SQL is generated:

C:Projectschapter12>python manage.py makemigrations
Migrations for 'arenas':
  arenasmigrations001_initial.py
    - Create model Arenas
    - Create model Counties
    - Create model Districts
    - Create model US_States

A new script has been generated and added to the migrations folder. This initial database migration script creates a Migration class and includes a number of migration operations using the CreateModel method. Each of these migrations creates operations will generate a new (empty) table in the chapter12 database. Migration classes also have methods for performing table alterations, when you need to add or remove fields.