Question

如下创建的django模型

from django.db import models

class Vender(models.Model):
    id  =models.IntegerField(primary_key=True)
    name = models.CharField(max_length=30)
    class Meta:
        db_table="vendor"

class car(models.Model):
    id  =models.IntegerField(primary_key=True)
    Vender=models.ForeignKey(Vender)
    carmodel =models.CharField(max_length=30)
    class Meta:
        db_table="car"

最初makemigration和migrate工作正常。然后我改变了一些模型字段和选项。之后得到以下错误。我是Django的新手。这种问题在生产中就会发生，我们如何解决现实交易数据的影响。

F:\Workspace\virtspace\demosrc>python manage.py migrate
Operations to perform:
  Apply all migrations: admin, contenttypes, base, auth, sessions
Running migrations:
  Applying base.0003_auto_20150110_2004...Traceback (most recent call last):
  File "manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "D:\Python27\lib\site-packages\django\core\management\__init__.py", line 385, in execute_from_command_line
    utility.execute()
  File "D:\Python27\lib\site-packages\django\core\management\__init__.py", line 377, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "D:\Python27\lib\site-packages\django\core\management\base.py", line 288, in run_from_argv
    self.execute(*args, **options.__dict__)
  File "D:\Python27\lib\site-packages\django\core\management\base.py", line 338, in execute
    output = self.handle(*args, **options)
  File "D:\Python27\lib\site-packages\django\core\management\commands\migrate.py", line 160, in handle
    executor.migrate(targets, plan, fake=options.get("fake", False))
  File "D:\Python27\lib\site-packages\django\db\migrations\executor.py", line 63, in migrate
    self.apply_migration(migration, fake=fake)
  File "D:\Python27\lib\site-packages\django\db\migrations\executor.py", line 97, in apply_migration
    migration.apply(project_state, schema_editor)
  File "D:\Python27\lib\site-packages\django\db\migrations\migration.py", line 107, in apply
    operation.database_forwards(self.app_label, schema_editor, project_state, new_state)
  File "D:\Python27\lib\site-packages\django\db\migrations\operations\fields.py", line 84, in database_forwards
    schema_editor.remove_field(from_model, from_model._meta.get_field_by_name(self.name)[0])
  File "D:\Python27\lib\site-packages\django\db\backends\schema.py", line 439, in remove_field
    self.execute(sql)
  File "D:\Python27\lib\site-packages\django\db\backends\schema.py", line 99, in execute
    cursor.execute(sql, params)
  File "D:\Python27\lib\site-packages\django\db\backends\utils.py", line 81, in execute
    return super(CursorDebugWrapper, self).execute(sql, params)
  File "D:\Python27\lib\site-packages\django\db\backends\utils.py", line 65, in execute
    return self.cursor.execute(sql, params)
  File "D:\Python27\lib\site-packages\django\db\utils.py", line 94, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "D:\Python27\lib\site-packages\django\db\backends\utils.py", line 65, in execute
    return self.cursor.execute(sql, params)
  File "D:\Python27\lib\site-packages\django\db\backends\oracle\base.py", line 916, in execute
    return self.cursor.execute(query, self._param_generator(params))
django.db.utils.DatabaseError: ORA-00904: "ID": invalid identifier

Answer 1

你不需要

id  =models.IntegerField(primary_key=True)

django为你添加它。别担心。

删除这些字段makemigrations，migrate，您就可以了。

Answer 2

可以保留

id=models.IntegerField(primary_key=True)

我多次遇到过这个问题，我使用的解决方案是，在更改现有模型的字段之前，运行：

python manage.py makemigrations --appName
python manage.py migrate --appName --fake

然后在模型中进行字段更改，运行如下： python manage.py makemigrations --appName python manage.py migrate --appName

你会看到所有绿色结果！

然后推理它因为：当你运行makemigrations --appName时，你可能会得到类似的东西： Migrations for 'app': 0001_initial.py: -Create model Vender - Create model car 但实际上，当你第一次创建数据库时，你已经创建了这两个模型，所以只是以假的方式进行迁移，它只会保留初始文件。然后进行更改，再次运行迁移，系统将自动检测更改

Django迁移问题

2 个答案: