如何在Django中使用South将数据从一个模型迁移到另一个模型？

在Django中，South是一个用于数据库迁移的第三方库。要将数据从一个模型迁移到另一个模型，请按照以下步骤操作：

安装South：

pip install south

将South添加到Django项目的INSTALLED_APPS中：

INSTALLED_APPS = (
    # ...
    'south',
    # ...
)

运行以下命令以创建迁移文件：

python manage.py schemamigration <app_name> --initial

在源模型和目标模型之间创建一个新的数据迁移文件：

python manage.py datamigration <app_name> <migration_name>

打开新创建的迁移文件，并编写迁移代码。例如，要将数据从OldModel迁移到NewModel，可以使用以下代码：

from django.db import models
from south.db import db
from south.v2 import DataMigration

class Migration(DataMigration):

    def forwards(self, orm):
        "Write your forwards methods here."
        # Note: Remember to use orm['appname.ModelName'] rather than "from appname.models..."
        for old_model in orm['<app_name>.OldModel'].objects.all():
            new_model = orm['<app_name>.NewModel'](
                # Copy fields from old_model to new_model
                field1=old_model.field1,
                field2=old_model.field2,
                # ...
            )
            new_model.save()

    def backwards(self, orm):
        "Write your backwards methods here."
        for new_model in orm['<app_name>.NewModel'].objects.all():
            old_model = orm['<app_name>.OldModel'](
                # Copy fields from new_model to old_model
                field1=new_model.field1,
                field2=new_model.field2,
                # ...
            )
            old_model.save()

    models = {
        # ...
        '<app_name>.OldModel': {
            'Meta': {'object_name': 'OldModel'},
            'field1': ('django.db.models.fields.CharField', [], {'max_length': '100'}),
            'field2': ('django.db.models.fields.IntegerField', [], {}),
            # ...
        },
        '<app_name>.NewModel': {
            'Meta': {'object_name': 'NewModel'},
            'field1': ('django.db.models.fields.CharField', [], {'max_length': '100'}),
            'field2': ('django.db.models.fields.IntegerField', [], {}),
            # ...
        },
        # ...
    }

    complete_apps = ['<app_name>']