How to Create a Django Form in Which the Form Field Values Are Unique If Blank

In this article, we show how to create a django from in which the form field values are unique if blank.

If you are dealing with a Django model, you must to specify the following parameters for the form field that you want to have unique values even if no value is specified.

name= models.CharField(unique=True, blank= True, null=True)

This handles the database aspect of the form field.

However, this will not work when you're creating the form for the user to enter in the data.

This is because the form field will automatically take no value entered into the field as an empty string.

Empty strings are not unique values in django models. So an empty string will trigger a non-unique value.

What we really want is a null value, which is unique, even if multiple database tables have it.

What is the easiest way to make sure that no value entered into a form field is entered in as a null value instead of an empty string, we go to the form field element and specify the parameter, empty_value=None

name= forms.CharField(widget=forms.TextInput(), required= False, empty_value=None)

With this parameter, if no value is specified for a form field, then it will be saved in the database as a null value instead of an empty string. null values are unique for each entry and do not violate the unique parameter, while empty strings would.

This is the most efficient way of ensuring that you can have a database element as unique, but that the unique parameter will not be violated if no value is entered in. Thus, the unique parameter will not be violated if no value is left blank but will be violated if an exact replicate is entered in for 2 distinct entries.

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