dumpdata > flush > loaddata.

[Maksych]

After commands:

python manage.py dumpdata > db.json
python manage.py loaddata db.json

All it`s okay, but after:

python manage.py flush
python manage.py loaddata db.json

Have exception:

django.db.utils.IntegrityError: Problem installing fixture 'D:\projects\python\django\ultrashop_backend\db.json': Could not load contenttypes.ContentType

[Mariusz Felisiak]

dumpdata dumps primary keys by default so IMO it's expected that such combination of commands fails. You should try:

django-admin dumpdata  --natural-foreign --natural-primary 

to avoid dumping auto primary keys (see ​documentation).

Closing per TicketClosingReasons/UseSupportChannels.

[Maksych]

No, I tell about:

python manage.py flush

My full actions:

django-admin startproject project .
python manage.py makemigrations
python manage.py migrate
python manage.py dumpdata > db.json
python manage.py loaddata db.json

And all it's okay, but after:

python manage.py flush
python manage.py loaddata db.json

Raised exception because content-types after flush is diferent betwen after migrate.

[Mariusz Felisiak]

This is documented behavior, please take a look at ​flush documentation:

Removes all data from the database and re-executes any post-synchronization handlers. The table of which migrations have been applied is not cleared. If you would rather start from an empty database and re-run all migrations, you should drop and recreate the database and then run migrate instead.

so flush removes all data from the database and re-executes post-synchronization handlers which recreates ContentType's with different IDs.