Django Django Models & ORM 2

Question 1

Which Django command applies pending database migrations?

Accepted Answer

python manage.py migrate

Answer

migrate applies all pending migration files to synchronize the database schema with the current state of your models.

Question 2

What is a QuerySet in Django?

Accepted Answer

A lazy collection of database objects that can be filtered and chained

Answer

A QuerySet represents a collection of database rows that can be filtered, ordered, and evaluated lazily when the data is actually needed.

Question 3

Which method would you call to create and save a new model instance in one step?

Accepted Answer

Model.objects.create()

Answer

Model.objects.create() instantiates the model and calls save() in a single database operation.

Question 4

What does `select_related()` do in a Django QuerySet?

Accepted Answer

Performs a SQL JOIN to fetch related objects in a single query

Answer

select_related() follows ForeignKey and OneToOneField relationships and performs a SQL JOIN, reducing the number of database queries.

Question 5

Which lookup suffix checks if a field value is in a given list in Django ORM?

Accepted Answer

__in

Answer

The __in lookup filters objects whose field value is contained in the provided list, generating a SQL IN clause.

Django Practice Test