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

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The main difference between null=True and blank=true is that null=True controls whether a field can store a NULL value in the database whereas blank=True controls whether a field can be left blank during form validation.

In Django, null=True and blank=True are field options that can be used for model fields, but they serve different purposes:

null=True

This option allows a field to store a NULL value in the database. When you set null=True for a field, it means that the field is allowed to have no value or an empty value at the database level. This option is most relevant for fields with a default value of NOT NULL, such as ForeignKey, OneToOneField, DateTimeField, etc.

Example

class Book(models.Model):
  title = models.CharField(max_length=100)
  publication_date = models.DateField(null=True)

The publication_date field can have a NULL value in the database, meaning a book can be saved without a publication date.

blank=True

This option allows a field to be left blank in forms, such as the Django admin or any other form you might use for user input. When you set a blank=True, it can be empty at the form validation level. If this option is not set, the field will be required, and submitting a form with an empty value for that field will result in a validation error.

Example

class Book(models.Model):
  title = models.CharField(max_length=100)
  author = models.CharField(max_length=100, blank=True)

Here, the author field can be left blank in a form, meaning a book can be saved without an author being specified.

You can use these options independently or together, depending on your requirements. For example, if you want a field to be optional both in the database and in forms, you can set both null=True and blank=True.

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