Generate unique id in django from a model field

Solution 1:

Since version 1.8 Django has UUIDField

import uuid
from django.db import models

class MyUUIDModel(models.Model):
    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    # other fields

Solution 2:

If you are using Django 1.8 or superior, madzohan's answer is the right answer.

Do it like this:

#note the uuid without parenthesis
eyw_transactionref=models.CharField(max_length=100, blank=True, unique=True, default=uuid.uuid4)

The reason why is because with the parenthesis you evaluate the function when the model is imported and this will yield an uuid which will be used for every instance created.

Without parenthesis you passed just the function needed to be called to give the default value to the field and it will be called each time the model is imported.

You can also take this approach:

class Paid(models.Model):
     user=models.ForeignKey(User)
     eyw_transactionref=models.CharField(max_length=100, null=True, blank=True, unique=True)

     def __init__(self):
         super(Paid, self).__init__()
         self.eyw_transactionref = str(uuid.uuid4())

     def __unicode__(self):
        return self.user