Django - populate table on startup with known values - django

Question

I have a Dog Model that have a "dog_type" field. i want the dog_type to be chosen from a list of pre-defined dog types, i DO NOT want to use a textfield with choices but a ForeignKey to a "DogType" Model. How could I populate the DogType Model with types on server startup? is this a good practice or a hack?
thanks.
code:
class Dog(Model):
name = CharField(...)
dog_type = ForeignKey(DogType)
class DogType(Model):
type_name = CharField(...)
type_max_hight = IntegerField(...)
etc....

Answer 1

You'll probably want to write a data migration that will add your choices in database.
Advantages of using this approach is that the data will be loaded in all your databases (production, dev, etc.)
(If you're not using migrations yet, you should consider it, it's a clean and well-supported way to manage your database)
In your django project, just run python manage.py shell makemigrations myapp --empty. This will create an empty migration file under myapp/migrations.
You can then edit it:
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from django.db import models, migrations
DEFAULT_DOG_TYPES = (
('Labrador', 90),
('Berger Allemand', 66),
('Chihuaha', -2),
)
def add_dog_types(apps, schema_editor):
DogType = apps.get_model('myapp', 'DogType')
for name, max_height in DEFAULT_DOG_TYPES:
dog_type = DogType(name=name, max_height=max_height)
dog_type.save()
def remove_dog_types(apps, schema_editor):
# This is used to migrate backward
# You can remove your dog types, or just pass
# pass
for name, max_height in DEFAULT_DOG_TYPES:
dog_type = DogType.objects.get(name=name, max_height=max_height)
dog_type.delete()
class Migration(migrations.Migration):
dependencies = [
# if you're already using migrations, this line will be different
('myapp', '0001_initial'),
]
operations = [
migrations.RunPython(add_dog_types, remove_dog_types),
]
After that, all you need to do is to run python manage.py syncdb.

Answer 2

not so far after, i found this it's called "fixtures"...
basically what you need to do is to place a "fixture" file in a format of your choice (JSON\YAML...) "myapp/fixtures/" for example, a JSON file would look like this:
[
{
"model": "myapp.person",
"pk": 1,
"fields": {
"first_name": "John",
"last_name": "Lennon"
}
},
{
"model": "myapp.person",
"pk": 2,
"fields": {
"first_name": "Paul",
"last_name": "McCartney"
}
}
]
then simply run from the command line:
python manage.py loaddata <filename> # file with no path!