From
"https://docs.djangoproject.com/en/2.0/topics/db/models/#automatic-primary-key-fields";,
it has a further definition of automatic primary key fields. In your
model just add "(primary_key=True)" to po_number field.
On Tuesday, 24 July, 2018 07:54 AM, Michael MacIntosh wrote:
Hi,
Aren't you looking for the AutoField?
https://docs.djangoproject.com/en/2.0/ref/models/fields/#autofield
It will automatically increment based on each record added to the table.
As an aside, the problem you are having is that in python, the first
argument to a class is a reference to the instance of that class. In
C this is often called a context. In C++ and Java it would be like
the `this` pointer. So you wouldn't generally pass "self" to a class
member.
Hope that helps!
On 7/23/2018 1:39 PM, Alexander Joseph wrote:
Hello,
I have a model ...
|
class PurchaseOrder(models.Model):
po_number = models.IntegerField(unique=True)
|
and a function ...
|
def get_po_number(self, *args, **kwargs):
if not self.id:
last_po = PurchaseOrder.objects.order_by('po_number').last()
if last_po:
last_po_num = last_po.po_number[-2:]
new_po_num = int(last_po_num) + 1
else:
new_po_num = '0001'
self.po_number = new_po_num
return self.po_number
|
what I'm trying to do is use the get_po_number() function to get a
default value for the po_number field in the model. However when I
set the default in the model like so...
|
class PurchaseOrder(models.Model):
po_number = models.IntegerField(unique=True,
default=get_po_number(self))
|
it says "NameError: name 'self' is not defined"
What am I doing wrong? Thanks!
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