Thanks Michael and Gerald. With an auto key field or primary key field would users still be able to input their own value? And if so how would I be able to give it a default attribute in a form that shows what the next number should be, if the user decides to choose to use the auto increment? Thanks again
On Mon, Jul 23, 2018, 6:36 PM Gerald Brown <[email protected]> wrote: > From > "https://docs.djangoproject.com/en/2.0/topics/db/models/#automatic-primary-key-fields"; > <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! > -- > You received this message because you are subscribed to the Google Groups > "Django users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at https://groups.google.com/group/django-users. > To view this discussion on the web visit > https://groups.google.com/d/msgid/django-users/6183c81e-54b8-4779-9bf3-c8c9e734f248%40googlegroups.com > <https://groups.google.com/d/msgid/django-users/6183c81e-54b8-4779-9bf3-c8c9e734f248%40googlegroups.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > > -- > This message has been scanned for viruses and dangerous content by > *E.F.A. Project* <http://www.efa-project.org>, and is believed to be > clean. > Click here to report this message as spam. > <http://lsefa1.linear-systems.com/cgi-bin/learn-msg.cgi?id=A29221028B6.A6CCB&token=d1d88836c3b5a866af3cc86dbf50fb46> > > > -- > You received this message because you are subscribed to the Google Groups > "Django users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at https://groups.google.com/group/django-users. > To view this discussion on the web visit > https://groups.google.com/d/msgid/django-users/945d5f35-e98b-b1f1-a527-32ff83687668%40linear-systems.com > <https://groups.google.com/d/msgid/django-users/945d5f35-e98b-b1f1-a527-32ff83687668%40linear-systems.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > > > -- > You received this message because you are subscribed to a topic in the > Google Groups "Django users" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/django-users/wpq8f815GGE/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > [email protected]. > To post to this group, send email to [email protected]. > Visit this group at https://groups.google.com/group/django-users. > To view this discussion on the web visit > https://groups.google.com/d/msgid/django-users/a37859a4-3c35-6f19-6a9b-ef997361bcee%40gmail.com > <https://groups.google.com/d/msgid/django-users/a37859a4-3c35-6f19-6a9b-ef997361bcee%40gmail.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Django users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/django-users. To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/CAGJrYjaMM7NdLHBXYxtzh5Ysii6qeepVTAGN2k3MHmZhnEmkrw%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
