如何将Django与PostgreSQL集成

Question

我已经设置了一切来迁移posgresql而不是sqlite。 我已经完成了数个教程中的所有操作，还安装了psycopg2，但无法迁移模型。 Settings.py数据库如下所示：

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.postgresql',
        'NAME': 'blog',
        'USER': 'postgres',
        'PASSWORD': 'xxxxxxx',
        'HOST': 'localhost',
        'PORT': '5432'
    },
}

当我运行迁移时，会出现此错误：

  Applying blogapp.0002_auto_20181031_1421...Traceback (most recent call last):
  File "manage.py", line 15, in <module>
    execute_from_command_line(sys.argv)
  File "C:\Users\PZAWA\AppData\Local\Programs\Python\Python37\lib\site-packages\django\core\management\__init__.py", line 381, in execute_from_command_line
    utility.execute()
  File "C:\Users\PZAWA\AppData\Local\Programs\Python\Python37\lib\site-packages\django\core\management\__init__.py", line 375, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "C:\Users\PZAWA\AppData\Local\Programs\Python\Python37\lib\site-packages\django\core\management\base.py", line 316, in run_from_argv
    self.execute(*args, **cmd_options)
  File "C:\Users\PZAWA\AppData\Local\Programs\Python\Python37\lib\site-packages\django\core\management\base.py", line 353, in execute
    output = self.handle(*args, **options)
  File "C:\Users\PZAWA\AppData\Local\Programs\Python\Python37\lib\site-packages\django\core\management\base.py", line 83, in wrapped
    res = handle_func(*args, **kwargs)
  File "C:\Users\PZAWA\AppData\Local\Programs\Python\Python37\lib\site-packages\django\core\management\commands\migrate.py", line 203, in handle
    fake_initial=fake_initial,
  File "C:\Users\PZAWA\AppData\Local\Programs\Python\Python37\lib\site-packages\django\db\migrations\executor.py", line 117, in migrate
    state = self._migrate_all_forwards(state, plan, full_plan, fake=fake, fake_initial=fake_initial)
  File "C:\Users\PZAWA\AppData\Local\Programs\Python\Python37\lib\site-packages\django\db\migrations\executor.py", line 147, in _migrate_all_forwards
    state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)
  File "C:\Users\PZAWA\AppData\Local\Programs\Python\Python37\lib\site-packages\django\db\migrations\executor.py", line 244, in apply_migration
    state = migration.apply(state, schema_editor)
  File "C:\Users\PZAWA\AppData\Local\Programs\Python\Python37\lib\site-packages\django\db\migrations\migration.py", line 124, in apply
    operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
  File "C:\Users\PZAWA\AppData\Local\Programs\Python\Python37\lib\site-packages\django\db\migrations\operations\fields.py", line 216, in database_forwards
    schema_editor.alter_field(from_model, from_field, to_field)
  File "C:\Users\PZAWA\AppData\Local\Programs\Python\Python37\lib\site-packages\django\db\backends\base\schema.py", line 523, in alter_field
    old_db_params, new_db_params, strict)
  File "C:\Users\PZAWA\AppData\Local\Programs\Python\Python37\lib\site-packages\django\db\backends\postgresql\schema.py", line 122, in _alter_field
    new_db_params, strict,
  File "C:\Users\PZAWA\AppData\Local\Programs\Python\Python37\lib\site-packages\django\db\backends\base\schema.py", line 627, in _alter_field
    new_default = self.effective_default(new_field)
  File "C:\Users\PZAWA\AppData\Local\Programs\Python\Python37\lib\site-packages\django\db\backends\base\schema.py", line 239, in effective_default
    return field.get_db_prep_save(default, self.connection)
  File "C:\Users\PZAWA\AppData\Local\Programs\Python\Python37\lib\site-packages\django\db\models\fields\related.py", line 937, in get_db_prep_save
    return self.target_field.get_db_prep_save(value, connection=connection)
  File "C:\Users\PZAWA\AppData\Local\Programs\Python\Python37\lib\site-packages\django\db\models\fields\__init__.py", line 790, in get_db_prep_save
    return self.get_db_prep_value(value, connection=connection, prepared=False)
  File "C:\Users\PZAWA\AppData\Local\Programs\Python\Python37\lib\site-packages\django\db\models\fields\__init__.py", line 956, in get_db_prep_value
    value = self.get_prep_value(value)
  File "C:\Users\PZAWA\AppData\Local\Programs\Python\Python37\lib\site-packages\django\db\models\fields\__init__.py", line 965, in get_prep_value
    return int(value)
TypeError: int() argument must be a string, a bytes-like object or a number, not 'User'

我不知道我该如何处理这个问题，sqlite的工作原理就像一个魅力，看起来像是扩展了用户模型的问题。 迁移文件：

class Migration(migrations.Migration):

    dependencies = [
        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
        ('blogapp', '0001_initial'),
    ]

    operations = [
        migrations.CreateModel(
            name='Comment',
            fields=[
                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
                ('comment_text', models.TextField(blank=True)),
                ('comment_author', models.CharField(help_text='Enter your nickname.', max_length=50)),
                ('comment_date', models.DateTimeField(auto_now_add=True)),
            ],
        ),
        migrations.AlterModelOptions(
            name='blogs',
            options={'verbose_name_plural': 'Blogs'},
        ),
        migrations.RemoveField(
            model_name='author',
            name='name',
        ),
        migrations.AddField(
            model_name='author',
            name='user',
            field=models.OneToOneField(null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='author', to=settings.AUTH_USER_MODEL),
        ),
        migrations.AddField(
            model_name='post',
            name='image',
            field=models.ImageField(default='media/default.jpg', upload_to='media'),
        ),
        migrations.AddField(
            model_name='post',
            name='post_text',
            field=models.TextField(blank=True),
        ),
        migrations.AlterField(
            model_name='post',
            name='author',
            field=models.ForeignKey(default=django.contrib.auth.models.User, null=True, on_delete=django.db.models.deletion.SET_NULL, to=settings.AUTH_USER_MODEL),
        ),
        migrations.AlterField(
            model_name='post',
            name='post_date',
            field=models.DateTimeField(auto_now_add=True),
        ),
        migrations.AddField(
            model_name='comment',
            name='post',
            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='blogapp.Post'),
        ),
    ]

Answer 1

问题是author设置的默认属性author = models.ForeignKey( User, on_delete=models.SET_NULL, null=True, default=User)应该是author = models.ForeignKey( User, on_delete=models.SET_NULL, null=True)现在一切正常。