[Django] #30813: dumpdata > flush > loaddata

[Django]

#30813: dumpdata > flush > loaddata
-------------------------------------+-------------------------------------
Reporter: Maksych | Owner: nobody
Type: Bug | Status: new
Component: Core | Version: 2.2
(Management commands) |
Severity: Normal | Keywords:
Triage Stage: | Has patch: 0
Unreviewed |
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
-------------------------------------+-------------------------------------
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

--
Ticket URL: <https://code.djangoproject.com/ticket/30813>
Django <https://code.djangoproject.com/>
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[Django]

#30813: dumpdata > flush > loaddata
-------------------------------------+-------------------------------------
Reporter: Maksych | Owner: nobody
Type: Bug | Status: new

Component: Core (Management | Version: 2.2
commands) |
Severity: Normal | Resolution:
Keywords: | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0

Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------

Changes (by Maksych):

* Attachment "photo_2019-09-27_18-12-35.jpg" added.

[Django]

#30813: dumpdata > flush > loaddata.

-------------------------------------+-------------------------------------
Reporter: Maksych | Owner: nobody

Type: Bug | Status: closed
Component: Core (Management | Version: master
commands) |
Severity: Normal | Resolution: invalid
Keywords: | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0

Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------

Changes (by felixxm):

* status: new => closed
* version: 2.2 => master
* resolution: => invalid

Comment:

`dumpdata` dumps primary keys by default which don't exist anymore after
`flush`, so 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
[https://docs.djangoproject.com/en/2.2/ref/django-admin/#dumpdata
documentation]).

Closing per TicketClosingReasons/UseSupportChannels.

--
Ticket URL: <https://code.djangoproject.com/ticket/30813#comment:1>

[Django]

#30813: dumpdata > flush > loaddata.

-------------------------------------+-------------------------------------
Reporter: Maksych | Owner: nobody

Type: Bug | Status: closed
Component: Core (Management | Version: master
commands) |
Severity: Normal | Resolution: invalid
Keywords: | Triage Stage:
| Unreviewed

Has patch: 0 | Needs documentation: 0

Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------

Comment (by 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.

--
Ticket URL: <https://code.djangoproject.com/ticket/30813#comment:2>

[Django]

#30813: dumpdata > flush > loaddata.

-------------------------------------+-------------------------------------
Reporter: Maksych | Owner: nobody

Type: Bug | Status: closed
Component: Core (Management | Version: master
commands) |
Severity: Normal | Resolution: invalid
Keywords: | Triage Stage:
| Unreviewed

Has patch: 0 | Needs documentation: 0

Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------

Comment (by felixxm):

This is documented behavior, please take a look at
[https://docs.djangoproject.com/en/2.2/ref/django-admin/#flush 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.

--
Ticket URL: <https://code.djangoproject.com/ticket/30813#comment:3>