Exception Type: AttributeError Exception Value: object has no attribute. What is wrong?

Question

I have a table in my database, region

class region(models.Model):
    region_name = models.CharField(primary_key=True,max_length=50, null=False)

    @classmethod
    def __unicode__(self):
        return "hello"

When I am trying to add several new instances of region into the DB through the admin interface, so the title of all the existing regions is "hello", so I update the __unicode__(self) function as

@classmethod
def __unicode__(self):
    return u'%s' %(self.region_name)

but now the admin displays

Exception Type: AttributeError
Exception Value:    
type object 'region' has no attribute 'region_name'

I have check my DB and there is region_name in the table for region. Can anyone help why this happens?

Community · Accepted Answer · 2017-05-23 10:25:52Z

4

You shouldn't be using a @classmethod. Just remove the @classmethod decorator for the __unicode__ function; the first parameter to a function decorated with @classmethod is the class itself, and not the model instance for your region instance.

This answer provides a good overview of the purpose and use of classmethod and staticmethod function decorators in Python.

edited May 23, 2017 at 10:25

CommunityBot

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answered May 29, 2013 at 8:53

Joseph Victor Zammit

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