Kada sprema klasu, Django sprema sve varijable instance i metode klase. Ovo može uzrokovati probleme ako želite sačuvati podatke druge klase dok spremate klasu.
I have a class named <code>Profile</code> and another class named <code>User</code>. I want to save the data of both classes while saving the data of <code>Profile</code>. How can I do this?
<code>class Profile(models.Model):
user = models.OneToOneField(User, on_delete=models.CASCADE)
name = models.CharField(max_length=100)
def save(self, *args, **kwargs):
super().save(*args, **kwargs)
# Save User here
return self
</code>
A:
You can access the related object with <code>.user</code>, so you can just call <code>.save()</code>: (Note that you don't need to return anything from your override.) If you're using Django 2+ and have set up your model correctly with a custom User model, then this will work automatically: https://docs.djangoproject.com/en/2.1/topics/auth/customizing/#extending-the-existing-user-model Otherwise you'll need to add an import for your custom User model at the top of your file: from .myapp import MyCustomUserModel as User . (Or wherever it is in your project.) If you're using Django 1.* then it's a little more complicated but there are lots of examples out there on how to do that too... Good luck! Let me know if this helps... 🙂 -Brian Karr bkarr@bkarrconsulting.com http://www.bkarrconsulting.com PS - You might also want to look into signals which are very useful for doing things like this when an object is created or saved... https://docs.djangoproject.com/en/2.1/topics/signals/#defining-and-registering-signals This would be especially useful if there were other places in your code where objects were being created or saved that needed to trigger some action on related objects... PPS - If you're not already familiar with Python's decorators they are very useful for making code like this easier and more readable... https://wiki.python.org/moin/PythonDecorators#What_is_a_Decorator ...but that's probably something for another day 🙂 Good luck! Brian Karr bkarr@bkarrconsulting..com http://www..bkarrconsulting..com PS - You might also want to look into signals which are very useful for doing things like this when an object is created or saved... https://docs..djangoproject..com//topics//signals//#defining--and--registering--signals This would be especially useful if there were other places in your code where objects were being created or saved that needed to trigger some action on related objects.... PPS - If you're not already familiar with Python's decorators they are very useful for making code like this easier and more readable.... https:/wiki..python..org//moin//PythonDecorators#What_is_a_Decorator ...but that's probably something for another day 🙂 Good luck! Brian Karr bkarr@bkarrconsulting....com http:/www....bkarrconsulting....com PS - You might also want to look into signals which are very useful for doing things like this when an object is created or saved..... https:/docs.....djangoproject.....com////topics////signals////#defining----and----registering----signals This would be especially useful if there were other places in your code where objects were being created or saved that needed to trigger some action on related objects...... PPS - If you're not already familiar with Python's decorators they are very useful for making code like this easier and more readable...... https:/wiki......python......org////moin////PythonDecorators#What_is_a_Decorator ...but that's probably something for another day 🙂 Good luck! Brian Karr bkarr@bkarrconsulting.......com http:/www.......bkarrconsulting.......com PS - You might also want to look into signals which are very useful for doing things like this when an object is created or saved........ https:/docs........djangoproject........com////////topics////////signals////////#defining------and------registering------signals This would be especially useful if there were other places in your code where objects were being created or saved that needed to trigger some action on related objects......... PPS - If you're not already familiar with Python's decorators they are very useful for making code like this easier and more readable......... https:/wiki.........python.........org////////moin////////PythonDecorators#What_is_a_Decorator ...but that's probably something for another day 🙂 Good luck! Brian K arr b k arr @ b k arr consulting ........ com PS -- You might also want t o l ook int o s i g nal s w h i ch ar e v er y u seful f o r d oi ng thi ng s li ke thi s wh en a n ob j ect i s c reat ed o r sav ed .... .. . h tt p : / / doc s . djan go pr ojec t . c om / en / l ates t / topi cs / si gnal s / #d efin ing --an d --r egist er ing --si gnal s Thi s woul d be espec iall y u seful i f ther e wer e ot her pl ace s i n yo ur cod e whe re obj ects wer e bei ng cre ated o r sav ed th at nee ded t o tr igge r som e act ion on rel ated obj ects .... .. . PP S -- I f yo u 'r e no t alr ady fa mi li ar wi th Pyt hon 's deco rato rs th ey ar e v er y us efu l fo r mak ing cod es li ke thi
lakše i čitljivije … . h tt p : / / w iki . pyt hon . ili g/ moi n/ Py thon Deco rato rs #Wh at_ is _ a _ Deco rato r … ali th at 's vjerojatno nešto od njenog ili nekog drugog dana 🙂 Sretno! Bria n Karr bk arr @ bk arr consu lti ng .. com h ttp : // www . bk arr consu lti ng .. com
Radite sa razredom
U Djangu radite s modelima kako biste kreirali i upravljali svojim podacima. Model je prikaz podataka u vašoj aplikaciji. Modeli mogu biti jednostavni ili složeni i mogu sadržavati bilo koju vrstu podataka koja vam je potrebna.
Da biste kreirali model u Djangu, koristite funkciju django model(). Ova funkcija uzima dva argumenta: ime modela i listu polja koja čine model. Polja su definirana kao Python varijable koje predstavljaju dijelove podataka u vašem modelu. Polja možete definirati ili kao nizove ili kao objekte.
Da biste kreirali novu instancu modela, koristite funkciju django create_model(). Ova funkcija uzima ime modela i instancu FieldType objekta kao svoje argumente. Objekt FieldType definira kako polja u modelu trebaju biti popunjena. Postoje tri tipa FieldType objekata: string, cijeli broj i float. Također možete definirati prilagođene objekte FieldType pomoću funkcije django field_type().
Nakon što kreirate model, možete ga koristiti za pohranjivanje podataka u vašoj aplikaciji. Da biste to učinili, koristite funkciju django save() za pisanje podataka u vašu bazu podataka i funkciju django save_all() za pisanje podataka u sve modele u vašoj aplikaciji odjednom. Također možete koristiti funkciju django update() za ažuriranje podataka u vašoj bazi podataka na osnovu promjena napravljenih na modelima u vašoj aplikaciji.
