Egy osztály mentésekor a Django elmenti az osztály összes példányváltozóját és metódusát. Ez problémákat okozhat, ha egy másik osztályadatot szeretne menteni az osztály mentése közben.
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
s könnyen és még jobban olvasható…. h tt p : / / w iki . pyt hon. vagy g/moi n/ Python Deco rato rs #Wh at_ is _ a _ Deco rato r … de ez valószínűleg valami más napján 🙂 Jó szerencsét! Bria n Karr bk arr @ bk arr consu lti ng .. com h ttp : / / www . bk arr consu lti ng .. com
Munka az osztállyal
A Djangoban modellekkel dolgozik az adatok létrehozásához és kezeléséhez. A modell az alkalmazásban lévő adatok reprezentációja. A modellek lehetnek egyszerűek vagy összetettek, és bármilyen típusú adatot tartalmazhatnak, amire szüksége van.
A Django-ban modell létrehozásához a django model() függvényt kell használni. Ez a függvény két argumentumot használ: a modell nevét és a modellt alkotó mezők listáját. A mezők Python-változókként vannak definiálva, amelyek a modellben lévő adatokat reprezentálják. A mezőket karakterláncként vagy objektumként is megadhatja.
Egy modell új példányának létrehozásához használja a django create_model() függvényt. Ez a függvény a modell nevét és a FieldType objektum egy példányát veszi argumentumaként. A FieldType objektum határozza meg, hogyan kell a modell mezőit feltölteni. A FieldType objektumok három típusa létezik: string, integer és float. Egyéni FieldType objektumokat is megadhat a django field_type() függvény segítségével.
Miután létrehozott egy modellt, használhatja azt adatok tárolására az alkalmazásban. Ehhez használja a django save() függvényt, hogy adatokat írjon az adatbázisába, és a django save_all() függvényt, hogy egyszerre írjon adatokat az alkalmazás összes modelljébe. A django update() függvényt is használhatja az adatbázisban lévő adatok frissítésére az alkalmazás modelljein végrehajtott módosítások alapján.
