django-models set record value depends on the existig ones-CodePudding

yo, I have simple Question but it's answer sames to be not ,at all, maybe even not exist !

anyway, I just want to set a django-model field value based on existing ones, LIKE:

class Person(models.Model):
    #here is the struggle
    people = len(Person.objects.all())
     
    name = medels.Charfield()
    #pass it as argument
    peopleBeforeYou = models.CharField(default= people-1)

the idea is to set the peopleBeforeYou field default value to that same model QuerySet len()

any idea ????!!!!

CodePudding user response：

You could move the function that counts the number of existing rows to a separate function outside of the class

def count_people():
    return Person.objects.count()


class Person(models.Model):
    peopleBeforeYou = models.IntegerField(default=count_people)