唯一约束失败的Django模型

Question

I'm working on a Django webapp.

I'm trying to create a user from signup form.

I made sure that there is no user in DB with that username and entered data in signup form and hit enter.

There is a default language field that is populated with txt in User user model.

I'm using the following function to populate that field.

def get_default_language():
    lang=Language.objects.get_or_create(
        name='Plain text',
        lang_code='text',
        slug='text',
        mime='text/plain',
        file_extension='.txt',
    )
    return lang[0].id

But it's giving me the below error

IntegrityError at /signup/

UNIQUE constraint failed: djangobin_language.lang_code

Here is the code for Language model

class Language(models.Model):
    name=models.CharField(max_length=100)
    lang_code=models.CharField(max_length=100, unique=True, verbose_name="Language Code")

Isn't it supposed to get or create the row in Language table? Why am I getting this error?

Answer 1

Your model is not complete. You.sre.passing different values for the get_or_create and because it can't find the exact object you are searching for than it tries to create one but the language code it's already used and you get the unique issue.

I suggest you to use a choices option on your language code field and pass a tuple with the ISO state definitions.

I also suggest you to retrieve based only the language code field and then decide or to update.the object based the other field passed or create a new language object. You must implement your own method to do that