Django Friends Meetup, 2014-03-25

django fixtures

they're not that bad!

Florian Demmer (@fdemmer)

what are they?

partial database dumps

via django apps/models

serialization: json, yaml, xml

why should we?

initial state & "configuration"

sample data for designers

and programmers

dropdb and back up in seconds

works offline

looks like...

[
    {
        "pk": 1,
        "model": "auth.group",
        "fields": {
            "name": "content_editor",
            "permissions": [
                [
                    "add_article",
                    "content",
                    "article"
                ],
              ... 

how does it work?

manage.py dumpdata > {file}

manage.py loaddata {name}

loaddata name?

fixtures directory, eg. app/fixtures

additional via settings.FIXTURE_DIRS

fixture name

eg. sample_data

app1/fixtures/sample_data.json

init_data fixture

special.

loaded automatically by syncdb & migrate

every time.

(up to 1.6)

to avoid --no-initial-data

(new in 1.5)

1.7?

https://docs.djangoproject.com/en/dev/releases/1.7/

"initial_data fixtures are no longer loaded for apps with migrations; if you want to load initial data for an app, we suggest you do it in a migration."

what is initial_data?

initial_data

whatever is save to overwrite every time.

no: defaults, examples, test data, ...

yes: permission groups, automatically updated data, ...

what about...?

sample_data, test_data

create fixtures, called like what they are!

initial_*

created once, updated by user/customer

loading fixtures

manage.py loaddata initial_data

manage.py loaddata sample_data

...

manage.py loaddata initial_exchangerates

...

creating fixtures

primary keys are dumped

foreign keys are dumped

default is ugly

{"pk": 1, "model": "auth.group", "fields": {"name": "content_editor", "permissions": [161, 163, 164, 165, 157, 158, 172,  
...

more useful output

manage.py dumpdata --indent 4 --natural

[
    {
        "pk": 1,
        "model": "auth.group",
        "fields": {
            "name": "content_editor",
            "permissions": [
                [
                    "add_article",
                    "content",
                    "article"
                ],
              ... 

because of reasons

indent for readability

formatting for git

valid json (no trailing ,)

natural keys to work with dbs with

different primary keys!

(eg. permissions)

done!