Django relationships between child and parent model - django

Question

I am busy with a project where I have two models and I'm not sure how to do as I am fairly new to programming.
what I would like to do is have a template that
renders all the instances of first model
and then on the same template I want to have all the sales associated with each of those instances as well as the instances with different states(for example if an instance of first model is linked to 2 sales that has a state of "Confirmed" it should say 2 next to that instance name.)
class QAAgent(models.Model):
user=models.OneToOneField(User,on_delete=models.SET_NULL,null=True)
Qa_name = models.CharField(max_length=15)
def __str__(self):
return self.user.username
States = (('Pending',"Pending"),("Confirmed","Confirmed"),("Requested","Requested),("Cancelled","Cancelled"),("Not interested","Not interested"))
class Sale(models.Model):
QA = models.ForeignKey(QAAgent,on_delete=models.SET_NULL,blank=True,
null=True,related_name="sale")
State = models.CharField(choices=States,default="Pending",max_length=15)
Date_created = models.DateTimeField(auto_now_add=True)
Date_edited = models.DateTimeField(auto_now=True)
def__str__(self):
return self.client_name + " " + self.client_surname
I am not sure how to reply to answers but thanks guys that worked perfectly!

Answer 1

To list all your entries of the first model including it's related items you can do the following. Just be sure to pass the correct queryset to the view context.
{% for entry in qa_agent %}
{{ entry.qa_name}}
{{ entry.user.name }}
{% for sale in entry.qa_sale.all %}
{{sale.category.state }}
{% endfor %}
{% endfor %}
For your second request just create a method in your model class which filters for the desired status. I've called it get_confirmed here.
class QAAgent(models.Model):
user = models.OneToOneField(User, on_delete=models.SET_NULL, null=True)
qa_name = models.CharField(max_length=15) # You had Qa_name before
def get_confirmed(self):
return self.qa_sale.filter(state="Pending") # just write a method like this one for each of the other statuses.
def __str__(self):
return self.user.username
And then modify your template code so it uses this method to display the confirmed ones.
{% for entry in qa_agent %}
{{ entry.qa_name}}
{{ entry.user.name }}
{{ entry.get_confirmed.count }} # <-- like this
{% endfor %}
Just a quick side note about python code styling.
For variables and function names use snake_case. for classes use CamelCase.
So for your model properties it's best to only use lower case letters and separate words using an underscore. For classes start with an uppercase letter and separate words by using an uppercase letter for the first letter of the new word. This is how it should look like:
states = (
("Pending", "Pending"),
("Confirmed", "Confirmed"),
("Requested", "Requested"),
("Cancelled", "Cancelled"),
("Not interested", "Not interested"),
)
class Sale(models.Model):
qa = models.ForeignKey(QAAgent, on_delete=models.SET_NULL, blank=True, null=True, related_name="qa_sale")
state = models.CharField(choices=States, default="Pending", max_length=15)
date_created = models.DateTimeField(auto_now_add=True)
date_edited = models.DateTimeField(auto_now=True)
def __str__(self):
return f"{self.client_name} {self.client_surname}" # If you concatenate strings use an fstring like I did here. It's more readable