Django Django Models & ORM 3

Question 1

What does the `unique=True` argument on a model field enforce?

Accepted Answer

That no two rows can have the same value for that field

Answer

Setting unique=True creates a UNIQUE constraint in the database, ensuring no two model instances share the same field value.

Question 2

Which abstract base class makes a model function as an abstract base, not creating its own database table?

Accepted Answer

Setting abstract = True in Meta

Answer

Setting abstract = True in the model's Meta class tells Django not to create a database table for that model; subclasses get their own tables with inherited fields.

Question 3

What does the `null=True` argument on a Django model field do?

Accepted Answer

Allows the field to store NULL in the database

Answer

null=True allows the database column to store a NULL value; for string-based fields, Django convention prefers blank=True with an empty string instead.

Question 4

Which Django ORM method deletes all objects matching a QuerySet?

Accepted Answer

QuerySet.delete()

Answer

Calling delete() on a QuerySet removes all matching objects from the database in an efficient bulk DELETE SQL statement.

Question 5

What is a Django migration squash used for?

Accepted Answer

Combining multiple migrations into a single migration file to reduce history

Answer

Squashing migrations uses python manage.py squashmigrations to merge a range of migrations into one, speeding up fresh database setups.

Django Practice Test

Django Practice Test

Django Django Models & ORM 3