Now that I have finished Django for Beginers i want to try and complete my first project that does NOT involve a step by step instruction on how to finish things.
I have a class UpdateIngredientView, its intended functionality is to target a resturants ingredient amount and than decrement or increment the inventory amount. Updating the price per unit would be vital as well. When I click on the hyperlink to that template_name I get the following error message. It is asking for a primary key or a slug. I would think the primary key would involve the values that I am updating.
So the first thing that I did was check Django For Beginners and it said that I should create a template and inside that template their is a url tag and inside that url tag there is a post.pk.
From that I guessed that the pk I need to supply is in the template. After reading the documentation it says I need to target the self.object which is being updated. I have targeted fields of ["quantity, “price_per_unit”] in my views.py so where do I post the object? How do I find the primary key value that I need?
<!-- start new HTML... -->
<a href="{% url 'post_edit' post.pk %}">+ Edit Blog Post</a> <!-- end new HTML... -->
{% endblock content %}
models.py
from django.db import models
from django.urls import reverse
# Create your models here.
class Ingredient(models.Model):
name = models.CharField(max_length = 20)
quantity = models.FloatField()
unit = models.CharField()
price_per_unit = models.FloatField()
# keep in mind that django automatically creates a primarky key column which can be referenced as
# id or .pk Ingredient.id or Ingreident.pk
# keep in mind that if you do use updateview you do not want to provide update view access to fields that you do not want edited in the column.
# this could result in users messing up things that they should not be allowed to touch.
class Meta:
ordering = ['name']
def __str__(self): # without the def_str__ method it will not label ingredient by name
return " " + self.name
def get_absolute_url(self):
return reverse("updateingredient", kwargs={"pk": self.pk})
class MenuItem(models.Model):
name = models.CharField(max_length = 20)
description = models.CharField(max_length = 200)
price = models.FloatField()
# I have set a primary key in hopes of having some way to identfy what has been ordered?
# id = models.AutoField(primary_key=True)
def requirements(self): # made for purchases sake and menu.html sake
requirements = RecipeRequirement.objects.filter(recipe=self)
return requirements
# this function will will grab all of the objects in the receipe requirements table
# and than it will filter what it grabs by the recipe being used and only grab what
# ingredients the recipe calls for.
# .filter will leave things as a list.
# ingredients is a method on the object.
# ingredient
def __str__(self):
return self.name
# go to the Receipe Requirements table.grab all of the recipe requiement data attributes. through .objects method.
# using.filter we tell python to only give me the objects when they equal this recipe.
# recipe is an attribute in the RecipeRequirement table line 44 see below.
# when that recipe field is equal to self grab the items that were used in making the recipe.
# self is an instance of an object. and that was
# when this item is equal to the one listed in the recipe grab this value.
# we need to access the ingredient cost and add it up. price per unit by the amount used and add it up.
#find me all of the recipe items you need to make this receipe.
#self is an instnace of the object.
#django djaffe cake as a menu item with descriptiona nd price. we pass that object in and say give me the recipe requirement
# is this object.
class RecipeRequirement(models.Model):
# a recipe_id will populate with django here
ingredient = models.ForeignKey(Ingredient,on_delete=models.CASCADE) # the ForeignKey will automatically reference the primary key that Django makes for us.
recipe = models.ForeignKey(MenuItem,on_delete=models.CASCADE) # the table did not have a concept of which ingredients were tied to what recipe. this line of code associates ingredients with reciepes.
quantity = models.FloatField()
def __str__(self):
return self.recipe.name + " " + self.ingredient.name # you can access values outside of the class to name things. this line of code details the recipe name and ingredient
class Purchases(models.Model):
# a purchase_id_field will populate with django here
menu_order = models.ForeignKey(MenuItem,on_delete=models.CASCADE) # this will let us see what menu items were ordered. # without the str method its an object method that you can use for calculations for purchases
timestamp = models.DateTimeField()
# menu order points to a row on the menu item table
# menu item is a table with a primary key called id.
# python will grab the menu item as an object and all of its data.
# menu order is a column in purchases that will have the menu item id in it.
# django djaffa cake has one id number. and if coffee has an id of two. it will find things by id number.
# each recipe has an id number of its own. on line 33 of models.py
# its saying follow those id numbers.
class Meta:
verbose_name = "Purchase"
# ask myself what does this table need information for
# what questions am I trying to answer for my boss or for my project?
# when inside of virtual enviornment just run python
# python manage.py
views.py
class UpdateIngredientView(UpdateView): # I am thinking this is an UpdateView
model = Ingredient
template_name = 'inventory/form_template.html'
fields = ["quantity", "price_per_unit"]
# success_url field attribute and reverse_lazy are used with updateview. upon successful completion of the viewd django
# will route the user to the url with the name pattern of ingredientupdate
success_url = reverse_lazy('ingredientupdate')
# fields = we need to input the fields of the columns that the provided model has.
Link to my Github: GitHub - strikeouts27/djangodelights
Error Message:
Traceback (most recent call last):
File "/Users/andrewstribling/Library/Python/3.9/lib/python/site-packages/django/core/handlers/exception.py", line 55, in inner
response = get_response(request)
File "/Users/andrewstribling/Library/Python/3.9/lib/python/site-packages/django/core/handlers/base.py", line 197, in _get_response
response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/Users/andrewstribling/Library/Python/3.9/lib/python/site-packages/django/views/generic/base.py", line 104, in view
return self.dispatch(request, *args, **kwargs)
File "/Users/andrewstribling/Library/Python/3.9/lib/python/site-packages/django/views/generic/base.py", line 143, in dispatch
return handler(request, *args, **kwargs)
File "/Users/andrewstribling/Library/Python/3.9/lib/python/site-packages/django/views/generic/edit.py", line 203, in get
self.object = self.get_object()
File "/Users/andrewstribling/Library/Python/3.9/lib/python/site-packages/django/views/generic/detail.py", line 46, in get_object
raise AttributeError(
Exception Type: AttributeError at /ingredient/update/
Exception Value: Generic detail view UpdateIngredientView must be called with either an object pk or a slug in the URLconf.
