update field with number of row in another table django

Question

I'm building a web crawler contain links blogs etc of x website ... , I have field called number_of_crawled_Links and I want to make the value of that filed is the number of rows in another model Where Links Stored i want the process to be automatically without making request any idea how to do that

Does this answer your question? https://stackoverflow.com/questions/3652736/django-update-queryset-with-annotation/50134728 — Iain Shelvington, Feb 05 '22 at 17:30
@Iain Shelvington it is not what I'm looking for , bcs i already updating it using mysql method but i wanna avoid this and use pure django — urek mazino, Feb 05 '22 at 17:41

NixonSparrow · Answer 1 · 2022-02-05T17:35:10.930

0

You cannot do that in fields directly, but it's good idea to do that as a method.

class ModelA(models.Model):
    some_field = models.TextField()

class ModelB(models.Model):
    model_a = models.ForeignKey(ModelA, on_delete=models.CASCADE)

    def get_some_field_value(self):
        return self.model_a.some_field

Then ModelB can get dynamically the value of ModelA field some_field. You can do it with any type of values.

edited Feb 05 '22 at 17:35

answered Feb 05 '22 at 17:28

NixonSparrow

6,130
1
6
18

somone closed my question and refer me to a useless answser, however i want omake that work automaticly every 10 minutes for examlple – urek mazino Feb 05 '22 at 17:32
I do not want field value but the count of all rows in another table ( model) – urek mazino Feb 05 '22 at 17:43
You can do anything in such method and return whatever you like. I don't know the details, so I cannot give you ready code. Share more related code or figure out the rest yourself. And for `cron` you have to get something like `django-scheduler` and put it in your `AppConfig`. – NixonSparrow Feb 05 '22 at 17:44

update field with number of row in another table django

1 Answers1