Migrations concept and workflow in Django - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a migration in Django?

A migration is a way Django tracks changes to your database schema. It helps update the database structure safely as your models change.

beginner

What command do you use to create new migrations after changing models?

You use python manage.py makemigrations to create migration files that describe the changes in your models.

beginner

What does the python manage.py migrate command do?

It applies the migration files to the database, updating the database schema to match your current models.

intermediate

Why should you always review migration files before applying them?

Because migrations change your database, reviewing helps avoid mistakes like deleting data or wrong schema changes.

beginner

What is the typical workflow when you change a Django model?

1. Change your model code.<br>2. Run python manage.py makemigrations to create migration files.<br>3. Review migration files.<br>4. Run python manage.py migrate to update the database.<br>5. Test your app to ensure it works.

Which command creates migration files after model changes?

A python manage.py makemigrations

B python manage.py migrate

C python manage.py runserver

D python manage.py collectstatic

The makemigrations command creates migration files describing model changes.

What does the migrate command do?

A Creates new migration files

B Updates the database schema based on migration files

C Starts the Django development server

D Deletes old migration files

The migrate command applies migrations to update the database schema.

Why is it important to review migration files before applying them?

A To automatically fix errors in models

B To speed up the migration process

C To avoid accidental data loss or wrong schema changes

D To generate documentation

Reviewing helps catch mistakes that could harm your database.

What happens if you change a model but forget to run makemigrations?

A The migration files will be deleted

B The server will crash immediately

C Django will auto-update the database

D The database won't update to match the model changes

Without migration files, the database stays the same and can cause errors.

Which file type stores the instructions for database changes in Django migrations?

A Python files (.py)

B JSON files (.json)

C SQL files (.sql)

D Text files (.txt)

Migration files are Python scripts that describe database changes.

Explain the step-by-step workflow of making and applying migrations in Django.

Think about what happens after you change your models.

Why are migrations important in Django projects? Describe their role and benefits.

Consider how migrations help manage database changes over time.