python - Django 中从 sqlite 迁移到 postgresql

Question

我想从 sqlite 迁移到 postgresql 数据库:
我安装了 postgresql 并在其 shell 上创建数据库，然后配置我的 django 设置如下:

'default': {
    'ENGINE': 'django.db.backends.postgresql',
    'NAME': 'dbname',
    'USER': 'username',
    'PASSWORD': 'dbpass',
    'HOST': 'localhost',
    'PORT': '',
}

或者:

'default': {
    'ENGINE': 'django.db.backends.postgresql_psycopg2',
    'NAME': 'dbname',
    'USER': 'username',
    'PASSWORD': 'dbpass',
    'HOST': 'localhost',
    'PORT': '',
}

但是什么时候python manage.py迁移我遇到了这个错误:

ValueError: invalid literal for int() with base 10: '0x000

完整回溯:

Operations to perform:
  Apply all migrations: delta_device, admin, menu, sessions, datapipeline, datacollector, siemens_s7, contenttypes, auth, settings
Running migrations:
  Rendering model states... DONE
  Applying delta_device.0002_auto_20171210_1631...Traceback (most recent call last):
  File "./manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 350, in execute_from_command_line
    utility.execute()
  File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 342, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/usr/local/lib/python2.7/dist-packages/django/core/management/base.py", line 348, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/usr/local/lib/python2.7/dist-packages/django/core/management/base.py", line 399, in execute
    output = self.handle(*args, **options)
  File "/usr/local/lib/python2.7/dist-packages/django/core/management/commands/migrate.py", line 200, in handle
    executor.migrate(targets, plan, fake=fake, fake_initial=fake_initial)
  File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/executor.py", line 92, in migrate
    self._migrate_all_forwards(plan, full_plan, fake=fake, fake_initial=fake_initial)
  File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/executor.py", line 121, in _migrate_all_forwards
    state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)
  File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/executor.py", line 198, in apply_migration
    state = migration.apply(state, schema_editor)
  File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/migration.py", line 123, in apply
    operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
  File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/operations/fields.py", line 201, in database_forwards
    schema_editor.alter_field(from_model, from_field, to_field)
  File "/usr/local/lib/python2.7/dist-packages/django/db/backends/base/schema.py", line 482, in alter_field
    old_db_params, new_db_params, strict)
  File "/usr/local/lib/python2.7/dist-packages/django/db/backends/base/schema.py", line 565, in _alter_field
    new_default = self.effective_default(new_field)
  File "/usr/local/lib/python2.7/dist-packages/django/db/backends/base/schema.py", line 210, in effective_default
    default = field.get_db_prep_save(default, self.connection)
  File "/usr/local/lib/python2.7/dist-packages/django/db/models/fields/__init__.py", line 728, in get_db_prep_save
    prepared=False)
  File "/usr/local/lib/python2.7/dist-packages/django/db/models/fields/__init__.py", line 720, in get_db_prep_value
    value = self.get_prep_value(value)
  File "/usr/local/lib/python2.7/dist-packages/django/db/models/fields/__init__.py", line 1853, in get_prep_value
    return int(value)
ValueError: invalid literal for int() with base 10: '0x000

怎么了？!

Answer 1

我决定从头开始解释这些说明:

1. 在您的计算机上安装 Postgres。

   • 首次安装 sudo apt-get install libpq-dev python-dev这是与 Django 完美配合的 Postgres 依赖项。
   • 然后，输入sudo apt-get install postgresql postgresql-contrib安装 Postgres 的命令。

2. 使用 sudo su - postgres 访问 Postgres命令。

3. 创建一个新数据库。 createdb <dbname>

4. 创建数据库用户(带密码)。 createuser -P <username>

5. 使用 psql 访问 shell命令。

6. 使用 GRANT ALL PRIVILEGES ON DATABASE <dbname> TO <username>; 授予此新用户对新数据库的访问权限命令。

7. 转储现有数据。 python3 manage.py dumpdata > datadump.json

8. 安装 Postgres 软件包。 pip install psycopg2

9. 将 settings.py 配置更改为以下内容:

DATABASES = {
 'default': {
     'ENGINE': 'django.db.backends.postgresql_psycopg2',
     'NAME': '<dbname>',
     'USER': '<username>',
     'PASSWORD': '<password>',
     'HOST': 'localhost',
     'PORT': '',  
 }
}

确保您可以连接到 Postgres 数据库。 python3 manage.py migrate --run-syncdb

在 Django shell 上运行此命令以排除内容类型数据。

python3 manage.py shell

>>> from django.contrib.contenttypes.models import ContentType
>>> ContentType.objects.all().delete()
>>> quit()

最后，加载您的数据。 python3 manage.py loaddata datadump.json