CODEWITHSUNDEEP
pythondjangodjango-models
user7693832
user7693832

Reputation: 6859

How can I set the field unique in django?

I have a model class:

class PysicalServer(models.Model):

    serial_number = models.CharField(max_length=64)  # I want to add the unique
    name = models.CharField(max_length=16)

I know use the primary_key can set unique, but the serial_number is not my id field, I can not use the primary_key, is there other property I can set field unique?

Upvotes: 43

Views: 69283

Answers (4)

Mauricio Cortazar
Mauricio Cortazar

Reputation: 4213

Just add unique=True in the field, so:

serial_number = models.CharField(max_length=64, unique=True)

Refer docs for more information.

Upvotes: 77

AnonymousUser
AnonymousUser

Reputation: 786

If you are looking for a unique case insensitive, then do this.

example "my NamE is John" and "MY naME is jOHN" should match and will not work to have 2,

because if you write "my NamE is John" it will become "My name is john".

and "MY naME is jOHN" will also become "My name is john".

models.py

1. add this code to the top.

capitalizeFirstChar = lambda s: s[:1].upper() + s[1:]

2. Then here is an example how to use it.

    class MyModel(models.Model):
        name = models.CharField(max_length=255, unique=True)
    
        def __str__(self):
            return self.name
    
# The save method to convert your text "MY naME is jOHN" to "My name is john"

        def save(self, force_insert=False, force_update=False):
            self.name = self.name.lower()
            self.name = capitalizeFirstChar(self.name)
    
            # If the name already exists
            if not Category.objects.filter(name__iexact=self.name).exists():
                super(Category, self).save(force_insert, force_update)

This solution sucks if you don't want the characters to change in capitalisation.

Upvotes: 1

Eyong Kevin Enowanyo
Eyong Kevin Enowanyo

Reputation: 1032

As mentioned by the other stackoverflowers above, you can use unique=True. but mind you that this won't work if you want to set a joined unique constraint. For example, if you want a combination of fields to be unique, then you should use models.UniqueConstraint as seen below

class Book(models.Model):
    title = models.CharField(max_length=300)
    sub_title = models.CharField(max_length=300)

    class Meta:
        constraints = [
            models.UniqueConstraint(fields=['title', 'sub_title'], name="%(app_label)s_%(class)s_unique")
        ]

    def __str__(self):
        return self.title

Upvotes: 9

Chris Goddy Chinedozie
Chris Goddy Chinedozie

Reputation: 93

The key word unique=True makes the title CharField unique.


class Book(models.Model):
    title= models.CharField(max_length=300, unique=True)

    def __str__(self):
        return self.title

http://www.learningaboutelectronics.com/Articles/How-to-make-a-database-table-field-unique-in-Django.php

Upvotes: 6

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