differentiate null=True, blank=True in django

Answer 1

Here is an example of the field with blank= True and null=True

description = models.TextField(blank=True, null= True)

In this case: blank = True: tells our form that it is ok to leave the description field blank

and

null = True: tells our database that it is ok to record a null value in our db field and not give an error.

Answer 2

Simple answer would be: Null is for Database tables while Blank is for Django Forms.

Answer 3

In Very simple words,

Blank is different than null.

null is purely database-related, whereas blank is validation-related(required in form).

If null=True, Django will store empty values as NULL in the database. If a field has blank=True, form validation will allow entry of an empty value. If a field has blank=False, the field will be required.

Answer 4

As said in Django Model Field reference: Link

Field options

The following arguments are available to all field types. All are optional.

null

Field.null

If True, Django will store empty values as NULL in the database. Default is False.

Avoid using null on string-based fields such as CharField and TextField because empty string values will always be stored as empty strings, not as NULL. If a string-based field has null=True, that means it has two possible values for "no data": NULL, and the empty string. In most cases, it’s redundant to have two possible values for "no data"; the Django convention is to use the empty string, not NULL.

For both string-based and non-string-based fields, you will also need to set blank=True if you wish to permit empty values in forms, as the null parameter only affects database storage (see blank).

Note

When using the Oracle database backend, the value NULL will be stored to denote the empty string regardless of this attribute

blank

Field.blank

If True, the field is allowed to be blank. Default is False.

Note that this is different than null. null is purely database-related, whereas blank is validation-related. If a field has blank=True, form validation will allow entry of an empty value. If a field has blank=False, the field will be required.

Answer 5

This table below demonstrates the main differences:

+--------------------------------------------------------------------+
| Purpose                  | null=True        | blank = True         |
|--------------------------|------------------|----------------------|
| Field can be empty in DB | Do this          | Unaffected           |
|--------------------------|------------------|----------------------|
| ModelForm(required field)| Unaffected       | field not required   |
|--------------------------|------------------|----------------------|
| Form Validation          | Unaffected       | field not required   |
|--------------------------|------------------|----------------------|
| on_delete=SET_NULL       | Need this        | Unaffected           |
+--------------------------------------------------------------------+

Answer 6

When you set null=true it will set null in your database if the field is not filled. If you set blank='true it will not set any value to the field.