I have Models for business Apps

class staff_name(models.Model): TITLE_CHOICES = ( ('Mr', 'Mr'), ('Miss', 'Miss'), ( 'Mrs', 'Mrs'), ( 'chief', 'chief'), ) titlename = models.CharField(max_length=10,choices=TITLE_CHOICES) firstname = models.CharField(max_length=150) surname = models.CharField(max_length=150) date = models.DateTimeField(auto_now=True) class meta: ordering = ["date"] get_latest_by = "date"

class inventory_transaction(models.Model):

stock_in = models.DecimalField(blank=True, null=True,max_digits=8, decimal_places=2)
stock_out = models.DecimalField(blank=True,null=True,max_digits=8, decimal_places=2)
Number_container = models.ForeignKey(container_identity)
staffs = models.ForeignKey(staff_name)
goods_details = models.ForeignKey(departments)
balance = models.DecimalField(max_digits=8, decimal_places=2)
date = models.DateTimeField(auto_now=True)

What i want to accomplish is

1. check if the staff have made entry to the table before if yes add the value for the stock in plus (last) balance field and assign to balance

   if no just assign stock in value to balance field and save these are my codes

These are my codes:

try:
    s = staffname.staffs_set.all().order_by("-date").latest() # staffname is the instant of the  class model staff_name

    e = s.staffs_set.create(stockin=vdataz,balance=s.balance + vdataz )  # e is the instant of the class model inventory_transaction

    e.save
    e.staffs.add(s)
    e.from_container.add(containersno)
    e.goods_details.add(department)

except ObjectDoesNotExist:
    e = staff_name.objects.create(stockin=vdataz,balance=vdataz )
    e.save
    e.staffs.add(staffname)
    e.from_container.add(containersno)
    e.goods_details.add(department)

I will really appreciate a solution Thanks

I hope it make more sense now. iam on online if you need more explanation just ask in the comment.Thank you for your help