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Sospeter Mongare
Sospeter Mongare

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Migrations in Django

Migrations are Django’s way of propagating changes you make to your models (adding a field, deleting a model, etc.) into your database schema. They’re designed to be mostly automatic, but you’ll need to know when to make migrations, when to run them, and the common problems you might run into.

The Commands¶
There are several commands which you will use to interact with migrations and Django’s handling of database schema:

migrate, which is responsible for applying and unapplying migrations.
makemigrations, which is responsible for creating new migrations based on the changes you have made to your models.
sqlmigrate, which displays the SQL statements for a migration.
showmigrations, which lists a project’s migrations and their status.
You should think of migrations as a version control system for your database schema. **makemigrations **is responsible for packaging up your model changes into individual migration files - analogous to commits - and migrate is responsible for applying those to your database.

The migration files for each app live in a “migrations” directory inside of that app, and are designed to be committed to, and distributed as part of, its codebase. You should be making them once on your development machine and then running the same migrations on your colleagues’ machines, your staging machines, and eventually your production machines.

Migrations will run the same way on the same dataset and produce consistent results, meaning that what you see in development and staging is, under the same circumstances, exactly what will happen in production.

Django will make migrations for any change to your models or fields - even options that don’t affect the database - as the only way it can reconstruct a field correctly is to have all the changes in the history, and you might need those options in some data migrations later on (for example, if you’ve set custom validators).

Happy Coding!!

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