AttributeError: 'Price' object has no attribute 'update'

Question

I got an error,AttributeError: 'Price' object has no attribute 'update' .I wrote

fourrows_transpose=list(map(list, zip(*fourrows)))
val3 = sheet3.cell_value(rowx=0, colx=9)
user3 = Companyransaction.objects.filter(corporation_id=val3).first()
if user3:
        area = Area.objects.filter(name="America").first()
        pref = Prefecture.objects.create(name="Prefecture", area=area)
        city = City.objects.create(name="City", prefecture=pref)
        price= Price.objects.create(city=city)

        pref.name = fourrows_transpose[0][0]
        pref.save()

        for transpose in fourrows_transpose[2:]:
            if len(transpose) == 5:
                if "×" in transpose or "○" in transpose:

                   city.name = "NY"
                   city.save()
                   price.update(upper1000="○",from500to1000="○",under500="○")

In models.py I wrote

class Area(models.Model):
    name = models.CharField(max_length=20, verbose_name='area', null=True)
class User(models.Model):
    user_id = models.CharField(max_length=200,null=True)
    area = models.ForeignKey('Area',null=True, blank=True)

class Prefecture(models.Model):
    name = models.CharField(max_length=20, verbose_name='prefecture')
    area = models.ForeignKey('Area', null=True, blank=True)

class City(models.Model):
    name = models.CharField(max_length=20, verbose_name='city')
    prefecture = models.ForeignKey('Prefecture', null=True, blank=True)
class Price(models.Model):
    upper1000 = models.CharField(max_length=20, verbose_name='u1000', null=True)
    from500to1000 = models.CharField(max_length=20, verbose_name='500～1000', null=True)
    under500 = models.CharField(max_length=20, verbose_name='d500', null=True)
    city = models.ForeignKey('City', null=True, blank=True)

I wanna put "○" to upper1000&from500to1000&under500 column of Price model, but it cannot be done because of the error.What is wrong in my code?How can I fix this?

Answer 1

.update is a method on querysets, not models. It's useful if you want to update a bunch of records that share some query criteria.

The normal way of updating an object you already have is to set its attributes and then save it.

price.upper1000 = "○"
price.from500to1000 = "○"
price.under500 = "○"
price.save()

Answer 2

django model instance has no attribute 'update' , the update is the method of django objects Manager class if you want to update single instance you can try:

Price.objects.filter(pk=price.pk).update(
    upper1000="○",
    from500to1000="○",
    under500="○"
)