Getting TypeError init missing 1 required positional argument on delete when trying to add parent table after child table with entries

Question

I have two classes in my sqlite database  a parent table named Categorie and the child table called Article  I created first the child table class and addes entries  So first I had this   class Article models Model       titre models CharField max length 100      auteur models CharField max length 42      contenu models TextField null True      date models DateTimeField          auto now add True          auto now False          verbose name  Date de parution             def   str   self           return self titre   And after I have added parent table  and now my models py looks like this   from django db import models    Create your models here  class Categorie models Model       nom   models CharField max length 30       def   str   self           return self nom   class Article models Model       titre models CharField max length 100      auteur models CharField max length 42      contenu models TextField null True      date models DateTimeField          auto now add True          auto now False          verbose name  Date de parution            categorie   models ForeignKey  Categorie        def   str   self           return self titre   So when I run python manage py makemigrations  lt my app name gt   I get this error   Traceback  most recent call last     File  manage py   line 15  in  lt module gt      execute from command line sys argv    File  C  Users lislis AppData Local Programs Python Python35-32 lib site-packages django-2 0-py3 5 egg django core management   init   py   line 354  in execute from command line     utility execute     File  C  Users lislis AppData Local Programs Python Python35-32 lib site-packages django-2 0-py3 5 egg django core management   init   py   line 330  in execute     django setup     File  C  Users lislis AppData Local Programs Python Python35-32 lib site-packages django-2 0-py3 5 egg django   init   py   line 24  in setup     apps populate settings INSTALLED APPS    File  C  Users lislis AppData Local Programs Python Python35-32 lib site-packages django-2 0-py3 5 egg django apps registry py   line 112  in populate     app config import models     File  C  Users lislis AppData Local Programs Python Python35-32 lib site-packages django-2 0-py3 5 egg django apps config py   line 198  in import models     self models module   import module models module name    File  C  Users lislis AppData Local Programs Python Python35-32 lib importlib   init   py   line 126  in import module     return  bootstrap  gcd import name level    package  level    File   lt frozen importlib  bootstrap gt    line 986  in  gcd import   File   lt frozen importlib  bootstrap gt    line 969  in  find and load   File   lt frozen importlib  bootstrap gt    line 958  in  find and load unlocked   File   lt frozen importlib  bootstrap gt    line 673  in  load unlocked   File   lt frozen importlib  bootstrap external gt    line 665  in exec module   File   lt frozen importlib  bootstrap gt    line 222  in  call with frames removed   File  C  Users lislis Django mon site blog models py   line 6  in  lt module gt      class Article models Model     File  C  Users lislis Django mon site blog models py   line 16  in Article     categorie   models ForeignKey  Categorie   TypeError    init     missing 1 required positional argument   on delete    I ve seen some similar issues in stackoverflow  but it seems to not be the same problem    init     missing 1 required positional argument    39 quantity  39

User · Answer

Post Django version 1 9  on delete became a required argument  i e  from Django 2 0    In older versions  it defaults to CASCADE   So  if you want to replicate the functionality that you used in earlier versions  Use the following argument  categorie   models ForeignKey  Categorie   on delete   models CASCADE   This will have the same effect as that was in earlier versions  without specifying it explicitly  Official Documentation on other arguments that go with on delete

User · Answer

Had a similar problem that resolved by adding both these two parameters to ForeignKey  null True  on delete models SET NULL

User · Answer

If you don t know which option to enter the params  Just want to keep the default value like on delete None before migration      on delete models CASCADE   This is a code snippet in the old version   if on delete is None      warnings warn           on delete will be a required arg for  s in Django 2 0  Set            it to models CASCADE on models and in existing migrations            if you want to maintain the current default behavior             See https   docs djangoproject com en  s ref models fields             django db models ForeignKey on delete                  self   class     name                get docs version                       RemovedInDjango20Warning  2      on delete   CASCADE

User · Answer

Since Django 2 x  on delete is required    Django Documentation     Deprecated since version 1 9  on delete will become a required   argument in Django 2 0  In older versions it defaults to CASCADE

User · Answer

From Django 2 0 on delete is required        user   models OneToOneField User  on delete models CASCADE    It will delete the child table data if the User is deleted  For more details check the Django documentation

User · Answer

Since Django 2 0 the ForeignKey field requires two positional arguments    the model to map to the on delete argument   categorie   models ForeignKey  Categorie   on delete models PROTECT    Here are some methods can used in on delete   CASCADE   Cascade deletes  Django emulates the behavior of the SQL constraint ON DELETE CASCADE and also deletes the object containing the ForeignKey   PROTECT   Prevent deletion of the referenced object by raising ProtectedError  a subclass of django db IntegrityError    DO NOTHING   Take no action  If your database backend enforces referential integrity  this will cause an IntegrityError unless you manually add an SQL ON DELETE constraint to the database field   you can find more about on delete by reading the documentation

User · Answer

If you are using foreignkey then you have to use  on delete models CASCADE  as it will eliminate the complexity developed after deleting the original element from the parent table  As simple as that   categorie   models ForeignKey  Categorie   on delete models CASCADE

User · Answer

This worked for me  pip install django-csvimport --upgrade

User · Answer

You can change the property categorie of the class Article like this   categorie   models ForeignKey       Categorie       on delete models CASCADE      and the error should disappear   Eventually you might need another option for on delete  check the documentation for more details   https   docs djangoproject com en 1 11 ref models fields  django db models ForeignKey  EDIT   As you stated in your comment  that you don t have any special requirements for on delete  you could use the option DO NOTHING         on delete models DO NOTHING

User · Answer

Here are available options if it helps anyone for on delete     CASCADE  DO NOTHING  PROTECT  SET  SET DEFAULT  SET NULL

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[python] Getting TypeError: init() missing 1 required positional argument: 'on_delete' when trying to add parent table after child table with entries