Kun tallennat luokan, Django tallentaa kaikki luokan ilmentymämuuttujat ja menetelmät. Tämä voi aiheuttaa ongelmia, jos haluat tallentaa toisen luokan tiedot samalla kun luokkaa tallennetaan.
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
on helpompi ja luettavampi…. h tt p : / / w iki . pyt hon. tai g/moi n/ Python Deco rato rs #Wh at_ on _ a _ Deco rato r … mutta th at todennäköisesti jotain asiaa tai muuta hänen päiväänsä 🙂 Onnea! Bria n Karr bk arr @ bk arr consu lti ng .. com h ttp : / / www . bk arr consu lti ng .. com
Työskentele luokan kanssa
Djangossa luot ja hallitset tietojasi mallien avulla. Malli on esitys sovelluksessasi olevista tiedoista. Mallit voivat olla yksinkertaisia tai monimutkaisia, ja ne voivat sisältää mitä tahansa tarvitsemaasi dataa.
Luodaksesi mallin Djangossa, käytät django model()-funktiota. Tämä funktio ottaa kaksi argumenttia: mallin nimen ja luettelon kentistä, jotka muodostavat mallin. Kentät määritellään Python-muuttujiksi, jotka edustavat mallissasi olevia tietoja. Voit määrittää kentät joko merkkijonoina tai objekteina.
Luodaksesi uuden mallin esiintymän, käytät django create_model() -funktiota. Tämä funktio ottaa mallin nimen ja FieldType-objektin esiintymän argumenteiksi. FieldType-objekti määrittää, kuinka mallin kentät tulee täyttää. FieldType-objekteja on kolmen tyyppisiä: merkkijono, kokonaisluku ja float. Voit myös määrittää mukautettuja FieldType-objekteja käyttämällä django field_type() -funktiota.
Kun olet luonut mallin, voit käyttää sitä tietojen tallentamiseen sovellukseesi. Tätä varten käytät django save()-funktiota tietojen kirjoittamiseen tietokantaan ja django save_all()-funktiota tietojen kirjoittamiseen kaikkiin sovelluksesi malleihin kerralla. Voit myös käyttää django update()-funktiota tietokannan tietojen päivittämiseen sovelluksesi malleihin tehtyjen muutosten perusteella.
