What is the difference between null=True and blank=True in Django?

In Django, null=True and blank=True are two different options that you can use when defining fields in a model to control how the database stores and validates data.

  1. null=True:

    • Applies at the database level.
    • Specifies whether the database should allow the field to have a NULL (empty) value.
    • It is relevant for database columns and determines whether the field can be stored as NULL in the database.
    • Use it for fields that can legitimately hold empty values, like text fields, dates, and numbers.
    • It is not applicable to non-database-backed fields like ManyToManyField.

  2. blank=True:

    • Applies at the validation level.
    • Specifies whether the field is allowed to be left blank in forms.
    • It is relevant for form validation and determines whether a field is required when a user submits a form.
    • Use it for fields that are optional from a user’s perspective, like optional text inputs or optional parts of a form.
    • It is not applicable to fields that aren’t used in forms.

Here’s a summary of the differences between null=True and blank=True:

  • If you want to allow an empty value (NULL) at the database level, use null=True.
  • If you want to allow an empty value (blank) at the validation level (form level), use blank=True.

For example, let’s say you have a Django model with a CharField named title. Here’s how you might use null=True and blank=True:

from django.db import models

class Article(models.Model):
title = models.CharField(max_length=100, null=True, blank=True)

In this case, null=True allows the title field to have NULL values in the database, and blank=True allows the field to be left blank in forms. This means that both the database column and form field can have empty values without causing issues.