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I'm creating a small web application to track my orders, i have two models:

Order(models.Model) " This model to record the new orders"

class Order(models.Model):
    customer= models.ForeignKey(Customer, null=True, on_delete= models.SET_NULL)
    product= models.ForeignKey(Product, null=True, on_delete= models.SET_NULL)
    date_created = models.DateTimeField(auto_now_add=True, null=True)
    status = models.CharField(max_length=200, null=True, choices=CATEGOTRIES)
    note = models.CharField(max_length=200, null=True)

OrderHistory(models.Model) " This model to record the changes for each order in any field"

class OrderHistory(models.Model):
    version_num = models.AutoField(primary_key=True)
    Order = models.ForeignKey(Order, null=True, on_delete= models.SET_NULL)
    customer= models.ForeignKey(Customer, null=True, on_delete= models.SET_NULL)
    product= models.ForeignKey(Product, null=True, on_delete= models.SET_NULL)
    date_created = models.DateTimeField(auto_now_add=True, null=True)
    status = models.CharField(max_length=200, null=True)
    note = models.CharField(max_length=200, null=True)

View:

def update_orders(request,pk):
     theOrder = Order.objects.get(id=pk)


    theHistory = createOrderHistory({
    'Order': theOrder.id,
    'customer': theOrder.customer, 
    'product': theOrder.product, 
    'date_created': theOrder.date_created,
    'status': theOrder.status, 
    'note': theOrder.note
    }) 

    print('The History of the order ',theHistory)
    UpdateForm = createOrder(instance=theOrder)
    theid = pk
    if request.method == 'POST':
        UpdateForm = createOrder(request.POST,instance=theOrder)
    if theHistory.is_valid():
        if UpdateForm.is_valid():
            theHistory.save()
            UpdateForm.save()
            return redirect('home')
    else:
        UpdateForm = createOrder(instance=theOrder) 

    context = {'UpdateForm':UpdateForm} 
    return render(request,'accounts/updateOrder.html',context)

In the View update_orders function am taking the current order and save it into OrderHistory and then i save the new changes into Order Model

it's working fine but the OrderHistory Model is not including the new change.

orderHistory to get the history of the order

def orderHistory(request,pk):
    theHistoryOfTheOrder = Order.objects.filter(id=pk).prefetch_related('Order')
    #theHistoryOfTheOrder = Order.objects.filter(id=pk)
    print('the query result is :',theHistoryOfTheOrder)
    context = {'theHistoryOfTheOrder':theHistoryOfTheOrder}
    return render(request,'accounts/orderHistory.html',context)

i tried to use prefetch_related() since i'm fetching multiple records but it's through an error 

Cannot find 'Order' on Order object, 'Order' is an invalid parameter to prefetch_related()

i need to get all the records in Order and OrderHistory with the same orderID also is this the right solution to preform History or is there another good way to do it?

mtf
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oammari a
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  • Are you asking how to save your changes or how to retrieve saved changes? And your intent was probably to filter `OrderHistory`, not `Orders`. – Ivan Starostin Apr 22 '20 at 11:01
  • i need to retrieve the data from both models since it's related Basically an outer join – oammari a Apr 22 '20 at 11:24
  • Please clarify which model is supposed to be on the left side of the join and on the right side. It's unclear from your code. – Ivan Starostin Apr 22 '20 at 12:24
  • Order should be on the left side so if there is nothing on the OrderHistory and one order on Order it will be retrieve, thank you Ivan – oammari a Apr 22 '20 at 12:41
  • Does this answer your question? [A left outer reverse select\_related in Django?](https://stackoverflow.com/questions/2975558/a-left-outer-reverse-select-related-in-django) – Ivan Starostin Apr 22 '20 at 12:49

0 Answers0