Django Django Forms & Validation 2

Question 1

How do you raise a validation error in a Django form's clean method?

Accepted Answer

raise forms.ValidationError('message')

Answer

Raising forms.ValidationError inside any clean method signals Django to mark the form as invalid and add the error to the field or non-field errors.

Question 2

What does setting `required=False` on a Django form field do?

Accepted Answer

Makes the field optional so empty values pass validation

Answer

By default form fields require a non-empty value; required=False allows the field to be submitted empty without triggering a validation error.

Question 3

Which Django form field is used to handle file uploads?

Accepted Answer

FileField

Answer

FileField validates and handles uploaded files in forms; the HTML form must also have enctype='multipart/form-data' set.

Question 4

What is the purpose of a form's `clean()` method?

Accepted Answer

To perform cross-field validation after individual field cleaning

Answer

The form-level clean() method runs after all individual field clean methods and is used to validate relationships between multiple fields.

Question 5

How do you render form errors for a specific field in a Django template?

Accepted Answer

Answer

Accessing form.fieldname.errors in a template returns an ErrorList of validation messages for that specific field.

Django Practice Test