how can I reference a field from one model to another model

[carlos]

Hello, 

I do not know if I'm asking the question correctly, but I need to call a field of one model in another model

example:

class ModelDad(models.Model):

    name = blablabla

class ModelChild1(....):

   fk(ModelDad)

   number = models.IntegerField()

class ModelChild2(....):

  fk(ModelDad)

  another_number = models.IntegerField()

   def make_proces(self):

      return self.another_number * ModelChild1.number #this is my question

how can I send a call number within the function (make_proces ) of ModelChild2

is posible????

--

att.

Carlos Rocha

[Mike Dewhirst]

You need a mechanism to find ModelChild1 and the Django ORM provides
Queries for exactly that.

There is a default model manager called 'objects' which you can use to
find instances of models. By that I mean you can pinpoint a row in the
database table which that model represents. For example ... (but to make
it clearer I'll adjust your models above slightly)

class ModelDad(models.Model):
    name = blablabla

class ModelChild1(models.Model):
   dad = models.ForeignKey(ModelDad)
   number = models.IntegerField()

class ModelChild2(models.Model):
   dad = models.ForeignKey(ModelDad)

   another_number = models.IntegerField()

   def make_proces(self):

        child1 = ModelChild1.objects.get(dad=self.dad)
        return self.another_number *child1.number

Visit Django documentation https://docs.djangoproject.com and scroll
down past "First steps" to  "The model layer" and click on a link in the
"Quersets" line. The answers will be in there.

>
> is posible????
>
>
>
> --
> att.
> Carlos Rocha

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[NAveeN Kumar Reddy]

You can use this where you want you to link tables with foreign key

models.ForeignKey(Model_Name,on_delete=models.CASCADE)

That's it  both tables will be in relation after migration of models into database

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Naveen Kumar  Reddy

[Anirudh Jain]

You can do this easily by creating creating an object of that model from which you want to get the value or input a value by using 'get_object_or_404' or 'get_list_or_404' by importing from django.shortucts. Reas about these two functions and difference between them in documentation.

Use them, for eg :-

 derive = get_object_or_404(ModelChild1, ModelDad=request.user) #object created of model ModelChild1

access = derive.number #will give the value of number that has been input by user

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[Amitesh Sahay]

hi, 

All the above should work. If you are working on django REST, then you can use ModelSerializer helper function. This will automatically sync with the table fields, and if there are any foreign key and primary key. They would be mapped automatically. 

Regards,

Amitesh Sahay

91-750 797 8619

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[carlos]

Thank Mike Dewhirst is working well

Cheers

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att.

Carlos Rocha