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

1 Answer

0 votes
by

null=True sets NULL (versus NOT NULL) on the column in your DB. Blank values for Django field types such as DateTimeField or ForeignKey will be stored as NULL in the DB.

blank determines whether the field will be required in forms. This includes the admin and your custom forms. If blank=True then the field will not be required, whereas if it's False the field cannot be blank.

The combo of the two is so frequent because typically if you're going to allow a field to be blank in your form, you're going to also need your database to allow NULL values for that field. The exception is CharFields and TextFields, which in Django are never saved as NULL. Blank values are stored in the DB as an empty string ('').

A few examples:

models.DateTimeField(blank=True) # raises IntegrityError if blank

models.DateTimeField(null=True) # NULL allowed, but must be filled out in a form

Obviously, Those two options don't make logical sense to use (though there might be a use case for null=True, blank=False if you want a field to always be required in forms, optional when dealing with an object through something like the shell.)

models.CharField(blank=True) # No problem, blank is stored as ''

models.CharField(null=True) # NULL allowed, but will never be set as NULL

CHAR and TEXT types are never saved as NULL by Django, so null=True is unnecessary. However, you can manually set one of these fields to None to force set it as NULL. If you have a scenario where that might be necessary, you should still include null=True.

Related questions

0 votes
    What is the difference between an uninitialized pointer and a null pointer?...
asked Jan 21, 2021 in Technology by JackTerrance
0 votes
    Write two points difference between Null loop and infinite loop Select the correct answer from above options...
asked Dec 17, 2021 in Education by JackTerrance
0 votes
    What is the difference between Django OneToOneField and ForeignKey Field?...
asked Jul 2, 2021 in Technology by JackTerrance
0 votes
    So in my project, I have a model Chat with many Messages. I want to have ChatSerializer with ... Questions for Interview, JavaScript MCQ (Multiple Choice Questions)...
asked Apr 20, 2022 in Education by JackTerrance
0 votes
    1 Choose the correct option:- 1) It is the blank area where you can draw and color in MS Paint. a) Line ... ans please tell me fast Select the correct answer from above options...
asked Dec 24, 2021 in Education by JackTerrance
0 votes
    1 Choose the correct option:- 1) It is the blank area where you can draw and color in MS Paint. a) ... give me ans subject computer Select the correct answer from above options...
asked Dec 24, 2021 in Education by JackTerrance
0 votes
    the………….. . toolbar in Microsoft word contains the tool buttons for opening and existing or a new blank word document Select the correct answer from above options...
asked Dec 22, 2021 in Education by JackTerrance
0 votes
    Tick (1) the correct answer and fill in the blank. 1. tab is used to perform Mail Merge. View Merging Mailings Select the correct answer from above options...
asked Dec 13, 2021 in Education by JackTerrance
0 votes
    I'm currently developing a custom module and for some reason it appends a blank space before anything I'm ... Questions for Interview, JavaScript MCQ (Multiple Choice Questions)...
asked Jul 30, 2022 in Education by JackTerrance
0 votes
    I am trying to get a thumbnail image from a video from a URL using AVFoundation but I am getting ... JavaScript Questions for Interview, JavaScript MCQ (Multiple Choice Questions)...
asked May 13, 2022 in Education by JackTerrance
0 votes
    I am trying to connect into the sql server but the server instance is blank I already try to search ... Questions for Interview, JavaScript MCQ (Multiple Choice Questions)...
asked May 7, 2022 in Education by JackTerrance
0 votes
    How do I check if a field is Blank in Salesforce using SOQL. Thanks Select the correct answer from above options...
asked Feb 2, 2022 in Education by JackTerrance
0 votes
    Fill in the blanks blank user the highest privileage Select the correct answer from above options...
asked Dec 19, 2021 in Education by JackTerrance
0 votes
    Fill in the blanks blank user the highest privileage Select the correct answer from above options...
asked Dec 18, 2021 in Education by JackTerrance
0 votes
    write the steps to create a table in MS Acess using blank table (create table) option Select the correct answer from above options...
asked Dec 17, 2021 in Education by JackTerrance
...