Code based unique constraint Django Model

Question

I have a Django model that looks like this:

class Categories(models.Model): """ Model for storing the categories """ name = models.CharField(max_length=8) keywords = models.TextField() spamwords = models.TextField() translations = models.TextField() def save(self, force_insert=False, force_update=False): """ Custom save method that converts the name to uppercase """ self.name = self.name.upper() super(Categories, self).save(force_insert, force_update)

Whenever the data is inserted or updated. I'd like to check that that a record with same name doesn't exists. It's a unique constraint that I'd like to implement via code and not the DB. The amount of data in this table is minuscule so the the performance hit is not an issue. If there is an constraint violation, I'd like to raise one of Django's inbuilt constraint exceptions instead of creating a custom one.

Could someone how me the best/fastest way to accomplish this?

Thanks.

msanders · Accepted Answer · 2010-07-07 12:53:29Z

8

In your model definition you can tell Django that 'name' should be unique:

name = models.CharField(max_length=8, unique=True)

A django.db.IntegrityError will be raised if you attempt to save two records with the same name.

answered Jul 7, 2010 at 12:53

msanders

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3 Comments

msanders Over a year ago

Hmmmm, OK... but your answer also reads from the DB with .get() - or am I interpreting 'not the DB' too literally? :-)

Mridang Agarwalla Over a year ago

Just out of curiosity. Is there a case-insensitive unique contraint in the Django models?

msanders Over a year ago

I don't think so. Interestingly it appears if you're using MySQL with utf-8 columns, you will already be getting case-insensitive constraints: docs.djangoproject.com/en/dev/ref/databases/#collation-settings

Ashok · Accepted Answer · 2010-07-07 12:52:31Z

-1

in the view

try: Category.objects.get(name='name') except Category.DoesNotExist: # call the save method of model

answered Jul 7, 2010 at 12:52

Ashok

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2 Comments

Mridang Agarwalla Over a year ago

Where would I write this? Would this be in the save method of the Model or the clean_name method?

Ashok Over a year ago

in the view, that handles the request

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