[Django]-Migrating Django fixtures?

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15đź‘Ť

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Here’s the process I used:

  1. Roll back the code to the revision that created the fixture in the first place. For example: svn up -r12345.

  2. Empty the database, then create it with manage.py syncdb --noinput --migrate

  3. Load the fixture with manage.py loaddata my_fixture.json

  4. Roll the code forward to now, with svn up

  5. Migrate the database with manage.py migrate

  6. Dump the data with manage.py dumpdata --indent=2 myapp >my_fixture.json

Note that you need to be careful when choosing the past revision to roll back to. In my case, I had some recent fixes that needed to be in place, so I actually had to pick and choose directories to roll back to specific revisions. Tedious, but better than hand-editing a 9,000-line JSON file.

Also, in step 6, be sure to dump the correct set of applications.

In the future, as I write migrations, I can do these steps again to keep all the fixtures up-to-date.

👤Ned Batchelder

1đź‘Ť

Why can’t you simply create a fresh .json file from your db. This is what I do when I need to create a new fixture.

python manage.py dumpdata <your_app> auth > test_data.json
👤Srikar Appalaraju

-3đź‘Ť

What’s the best way to move my fixtures forward as I migrate my database?

It’s too late.

As you migrate your database you need to loaddata and dumpdata.

One it stops working, it’s too late.

A possible fallback is to write a short script to load the JSON fixtures into memory,
and then “manually” build database objects.

with open( "somefile.json", "r" ) as data:
    for obj in json.load( data ):
        if obj['model'] == 'someapp.somemodel':
            SomeNewModel.objects.create( 
                field = obj['fields']['element']
                ...
                )

With something along those lines, you might be able to construct a database using your current schema and legacy fixtures.

👤S.Lott

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