Pri ukladaní triedy Django uloží všetky premenné inštancie a metódy triedy. To môže spôsobiť problémy, ak chcete pri ukladaní triedy uložiť údaje inej triedy.
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
je jednoduchšia a čitateľnejšia... h tt p : / / w iki . pyt hon . alebo g/ moi n/ Python Decor r to rs #Wh at_ je _ a _ Decor rato r ... ale to je pravdepodobne niečo pre iný deň 🙂 Veľa šťastia! Bria n Karr bk arr @ bk arr consu lti ng .. com h ttp : / / www . bk arr consu lti ng .. com
Pracujte s triedou
V Django pracujete s modelmi a vytvárate a spravujete svoje údaje. Model je reprezentácia údajov vo vašej aplikácii. Modely môžu byť jednoduché alebo zložité a môžu obsahovať akýkoľvek typ údajov, ktoré potrebujete.
Ak chcete vytvoriť model v Django, použite funkciu django model(). Táto funkcia má dva argumenty: názov modelu a zoznam polí, ktoré tvoria model. Polia sú definované ako premenné Pythonu, ktoré predstavujú časti údajov vo vašom modeli. Polia môžete definovať buď ako reťazce alebo ako objekty.
Ak chcete vytvoriť novú inštanciu modelu, použite funkciu django create_model(). Táto funkcia berie ako svoje argumenty názov modelu a inštanciu objektu FieldType. Objekt FieldType definuje, ako majú byť polia v modeli vyplnené. Existujú tri typy objektov FieldType: string, integer a float. Môžete tiež definovať vlastné objekty FieldType pomocou funkcie django field_type().
Po vytvorení modelu ho môžete použiť na ukladanie údajov vo vašej aplikácii. Ak to chcete urobiť, použite funkciu django save() na zapisovanie údajov do vašej databázy a funkciu django save_all() na zapisovanie údajov do všetkých modelov vo vašej aplikácii naraz. Môžete tiež použiť funkciu django update() na aktualizáciu údajov vo vašej databáze na základe zmien vykonaných v modeloch vo vašej aplikácii.
