The default values of null and blank are False.
Null: It is database-related. Defines if a given database column will accept null values or not.
Blank: It is validation-related. It will be used during forms validation, when calling form.is_valid().
That being said, it is perfectly fine to have a field with null=True and blank=False. Meaning on the database level the field can be NULL, but in the application level it is a required field.
Now, where most developers get it wrong: Defining null=True for string-based fields such as CharField and TextField. Avoid doing that. Otherwise, you will end up having two possible values for “no data”, that is: None and an empty string. Having two possible values for “no data” is redundant. The Django convention is to use the empty string, not NULL.
