Django/Python：如何为 migration/migrate 数据遍历字典中的列表

Question

我正在尝试设置迁移文件以将值加载到我的表中。我正在我的表格中创建 countries/states。我想以一种可以将每个国家放在自己的文件中的方式进行设置，然后运行遍历所有移民国家。我成功地分别获得了所有的名字，但我正在努力让它变得更容易。

更新：

感谢您的帮助，我已经按照我想要的方式工作了。这是我的最终结果。

型号：

class Country(models.Model):
    country_code = models.CharField(
        primary_key=True,
        max_length=3,
        verbose_name='Country Code',
        help_text='3 Letter Country Code',
        )
    country_name = models.CharField(
        "Country Name",
        max_length=30,
        unique=True,
        )

class State(models.Model):
    key = models.AutoField(
        primary_key=True,
        )
    country = models.ForeignKey(
        'Country',
        on_delete=models.CASCADE,
        verbose_name='Country',
        help_text='State located in:'
        )
    state_name = models.CharField(
        "State or Province",
        max_length=100,
        )
    state_code = models.CharField(
        "State Code",
        max_length=30,
        help_text='Mailing abbreviation'
        )

迁移数据文件：

"""
Canada migration information.
    Stored in dictionary = canada

copy into migration_data_migrate_countries
    from .migration_country_Canada import canada

Models:
    Country
    State
"""

# Country
import_country = ['CAN', 'CANADA',]

# State
import_states = [

    ['AB', 'ALBERTA'],
    ['BC', 'BRITISH COLUMBIA'],
    ['MB', 'MANITOBA'],
    etc...

]

# 'import' into migration file
canada = {

    'country': import_country,
    'states': import_states,

}

第二个国家文件：

# Country
import_country = ['USA', 'UNITED STATES',]

# State
import_states = [

    ['AL', 'ALABAMA'],
    ['AK', 'ALASKA'],
    ['AZ', 'ARIZONA'],
    etc...

]

# 'import' into migration file
united_states = {

    'country': import_country,
    'states': import_states,

    }

导入方式：

# Keep imports alphabetized by country name.
from .migration_country_Canada import canada
from .migration_country_UnitedStates import united_states

list_of_countries = [

    canada,
    united_states,

]


def migrate_countries(apps, schema_editor):
    Country = apps.get_model('app', 'Country')
    State = apps.get_model('app', 'State')

    for country in list_of_countries:
        import_country = country['country']
        states = country['states']

        current_country = Country.objects.get_or_create(
                                country_code=import_country[0],
                                country_name=import_country[1]
                                )

        # False = already exists. True = created object.
        print(import_country, current_country)

        for s in states:
            state_country = Country.objects.get(
                                country_code=import_country[0])
            state = State.objects.get_or_create(
                            country=state_country,
                            state_code=s[0],
                            state_name=s[1],
                            )

            # False = already exists. True = created object.
            print(s, state)

然后我运行python3 manage.py makemigrations --empty app编辑迁移文件：

from django.db import migrations

from app.migration_countries.migration_data_migrate_countries import *


class Migration(migrations.Migration):

    dependencies = [
        ('app', '0001_initial'),
    ]

    operations = [
        migrations.RunPython(migrate_countries),
    ]

然后运行 python3 manage.py migrate 并在终端中获取结果

...               # Added Canada first which is why YUKON is False
['YT', 'YUKON'] (<State: State object (75)>, False)
['USA', 'UNITED STATES'] (<Country: Country object (USA)>, True)
['AL', 'ALABAMA'] (<State: State object (76)>, True)
...

当我想添加另一个国家时，france，我制作了一个 france 文件并将我的 list 更改为：

list_of_countries = [

    canada,
    france,
    united_states,

]

我所做的任何更改都应该保持最新。希望。任何建议，请随时告诉我。

Answer 1

我猜你最初尝试处理此任务的方式是问题所在。我认为你应该更新你的词典：

canada = {
    'country': import_country,
    'states': import_states,
}

请记住，键应该是不可变对象。

for country in list_of_countries:
    import_country = country['country']
    states = country['states']

    current_country = Country.objects.get_or_create(
                                country_code=c[0],
                                country_name=c[1]
                                )
    current_country.states = states

我不确定你想要达到什么目的，但如果你提供更好的描述，我可以更新我的答案。

Django/Python：如何为 migration/migrate 数据遍历字典中的列表

Django/Python: How to iterate through a list in a dictionary for migration/migrate data

iteration

django

data-migration

python-3.x