Django. Comparing the model fields before saving for the admin panel

Question

I'm new to Django and I have a question (Yes, yes, I was looking for and did't find ...). There are two models:

class CounterDetail(models.Model):
counter = models.ForeignKey(Counter, on_delete=models.CASCADE)
date_placing = models.DateField(auto_now=False, auto_now_add=False, blank=False, null=False)
verifying_period_mounts = models.IntegerField(blank=False, null=False)

and

class Detail(models.Model):
counterdetail = models.ForeignKey(CounterDetail, on_delete=models.CASCADE)
date_last_verification = models.DateField(auto_now=False, auto_now_add=False, blank=False, null=False)
date_obxoda = models.DateField(auto_now=False, auto_now_add=False, blank=False, null=False)

How to implement the check when adding an entry to the second model through the admin panel: field date_obxoda = models.DateField(auto_now=False, auto_now_add=False, blank=False, null=False)more then date_placing = models.DateField(auto_now=False, auto_now_add=False, blank=False, null=False) from another model.

I'm looking for a method (preferably as an overridden save () method in the model) when adding records via the admin panel, to verify that the date from the second model (with a foreign key) is greater than the first.

Please give an example, thank you.

Django provide a [ManyToManyField](https://docs.djangoproject.com/en/2.0/topics/db/examples/many_to_many/), so you don't need Foreign key referencing to each other in both model. Also could you please explain a bit more what you want to do ? — Sumeet Kumar, Jan 24 '18 at 17:59
Hah.) They do not refer to each other. The first model refers to a completely different table, but that's another story ...I added a paragraph with a more detailed description. — Aleks Porberevskiy, Jan 24 '18 at 18:15
ohh.. my bad, I didn't notice. well posted an answer, check it. — Sumeet Kumar, Jan 24 '18 at 18:23
related: https://stackoverflow.com/q/23361057, https://stackoverflow.com/q/25647498 — djvg, Sep 14 '22 at 17:02

score 0 · Accepted Answer · answered Jan 24 '18 at 18:23

0

you can override Detail model save method like

def save(self, *args, **kwargs):
    super(Detail, self).save(*args, **kwargs)
    if self.date_obxoda > self.counterdetail.date_placing :
        #do_something

let me know if this help

answered Jan 24 '18 at 18:23

Sumeet Kumar

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Thank you friend. But there was a new question) How to generate an error so that in the administrator of the panel the field turned red. I was able to only display the ValidationError to the full screen) – Aleks Porberevskiy Jan 24 '18 at 18:38
override the `clean()' method just like you did to `save()` with same code. `def clean(self): if self.date_obxoda > self.counterdetail.date_placing : #do_something return self.cleaned_data` – Sumeet Kumar Jan 24 '18 at 18:46
Bro, I really appreciate it. – Aleks Porberevskiy Jan 24 '18 at 18:52
happy to help you bro ;) – Sumeet Kumar Jan 24 '18 at 18:53

Django. Comparing the model fields before saving for the admin panel

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