如何在两个 Django 应用程序之间移动模型(Django 1.7)

2021-11-20 00:00:00 python django database mysql schema-migration

所以大约一年前，我开始了一个项目，和所有新开发人员一样，我并没有真正关注结构，但是现在我与 Django 一起走得更远，它开始出现我的项目布局主要是我的模型结构可怕.

So about a year ago I started a project and like all new developers I didn't really focus too much on the structure, however now I am further along with Django it has started to appear that my project layout mainly my models are horrible in structure.

我的模型主要保存在一个应用程序中，实际上这些模型中的大多数应该在它们自己的单独应用程序中，我确实尝试解决了这个问题并将它们向南移动，但是由于外键等，我发现这很棘手而且非常困难.

I have models mainly held in a single app and really most of these models should be in their own individual apps, I did try and resolve this and move them with south however I found it tricky and really difficult due to foreign keys ect.

然而，由于 Django 1.7 和对迁移的内置支持，现在有更好的方法来做到这一点吗?

However due to Django 1.7 and built in support for migrations is there a better way to do this now?

推荐答案

我正在删除旧答案，因为可能会导致数据丢失.正如 ozan 提到的，我们可以在每个应用程序中创建 2 个迁移.这篇文章下面的评论是指我的旧答案.

I am removing the old answer as may result in data loss. As ozan mentioned, we can create 2 migrations one in each app. The comments below this post refer to my old answer.

第一次迁移以从第一个应用程序中删除模型.

First migration to remove model from 1st app.

$ python manage.py makemigrations old_app --empty

编辑迁移文件以包含这些操作.

Edit migration file to include these operations.

class Migration(migrations.Migration):

    database_operations = [migrations.AlterModelTable('TheModel', 'newapp_themodel')]

    state_operations = [migrations.DeleteModel('TheModel')]

    operations = [
      migrations.SeparateDatabaseAndState(
        database_operations=database_operations,
        state_operations=state_operations)
    ]

第二次迁移取决于第一次迁移并在第二个应用程序中创建新表.将模型代码移至第二个应用程序后

Second migration which depends on first migration and create the new table in 2nd app. After moving model code to 2nd app

$ python manage.py makemigrations new_app

并将迁移文件编辑为这样的内容.

and edit migration file to something like this.

class Migration(migrations.Migration):

    dependencies = [
        ('old_app', 'above_migration')
    ]

    state_operations = [
        migrations.CreateModel(
            name='TheModel',
            fields=[
                ('id', models.AutoField(verbose_name='ID', serialize=False, auto_created=True, primary_key=True)),
            ],
            options={
                'db_table': 'newapp_themodel',
            },
            bases=(models.Model,),
        )
    ]

    operations = [
        migrations.SeparateDatabaseAndState(state_operations=state_operations)
    ]

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