Django 找不到 psycopg2 模塊

Question

我正在 Amazon EC2 服務器上安裝 python 3.5、django 1.10 和 psycopg2 2.7.1，以便使用 Postgresql 數據庫。 我在虛擬環境中使用 python 3，並遵循經典安裝步驟：

cd /home/mycode
virtualenv-3.5 p3env
source p3env/bin/activate
pip install django
cd kenbot
django-admin startproject kenbot
pip install psycopg2

然后我在我的項目中編輯了 settings.py 文件來定義 DATABASE 設置：

DATABASES = {
'default': {
    'ENGINE': 'django.db.backends.postgresql_psycopg2',
    'NAME': 'deleted',
    'USER': 'deleted',
    'PASSWORD': 'deleted',
    'HOST': 'deleted',
    'PORT': '5432',
}   

最后我輸入（仍然在虛擬環境中）：

python manage.py makemigrations

並得到以下錯誤：

Traceback (most recent call last):
  File "/home/mycode/p3env/local/lib/python3.5/dist-packages/django/db/backends/postgresql/base.py", line 20, in <module>
    import psycopg2 as Database
ImportError: No module named 'psycopg2'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "manage.py", line 22, in <module>
    execute_from_command_line(sys.argv)
  File "/home/mycode/p3env/local/lib/python3.5/dist-packages/django/core/management/__init__.py", line 367, in execute_from_command_line
    utility.execute()
  File "/home/mycode/p3env/local/lib/python3.5/dist-packages/django/core/management/__init__.py", line 341, in execute
    django.setup()
  File "/home/mycode/p3env/local/lib/python3.5/dist-packages/django/__init__.py", line 27, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "/home/mycode/p3env/local/lib/python3.5/dist-packages/django/apps/registry.py", line 108, in populate
    app_config.import_models(all_models)
  File "/home/mycode/p3env/local/lib/python3.5/dist-packages/django/apps/config.py", line 199, in import_models
    self.models_module = import_module(models_module_name)
  File "/home/mycode/p3env/lib64/python3.5/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 986, in _gcd_import
  File "<frozen importlib._bootstrap>", line 969, in _find_and_load
  File "<frozen importlib._bootstrap>", line 958, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 673, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 662, in exec_module
  File "<frozen importlib._bootstrap>", line 222, in _call_with_frames_removed
  File "/home/mycode/p3env/local/lib/python3.5/dist-packages/django/contrib/auth/models.py", line 4, in <module>
    from django.contrib.auth.base_user import AbstractBaseUser, BaseUserManager
  File "/home/mycode/p3env/local/lib/python3.5/dist-packages/django/contrib/auth/base_user.py", line 52, in <module>
    class AbstractBaseUser(models.Model):
  File "/home/mycode/p3env/local/lib/python3.5/dist-packages/django/db/models/base.py", line 119, in __new__
    new_class.add_to_class('_meta', Options(meta, app_label))
  File "/home/mycode/p3env/local/lib/python3.5/dist-packages/django/db/models/base.py", line 316, in add_to_class
    value.contribute_to_class(cls, name)
  File "/home/mycode/p3env/local/lib/python3.5/dist-packages/django/db/models/options.py", line 214, in contribute_to_class
    self.db_table = truncate_name(self.db_table, connection.ops.max_name_length())
  File "/home/mycode/p3env/local/lib/python3.5/dist-packages/django/db/__init__.py", line 33, in __getattr__
    return getattr(connections[DEFAULT_DB_ALIAS], item)
  File "/home/mycode/p3env/local/lib/python3.5/dist-packages/django/db/utils.py", line 211, in __getitem__
    backend = load_backend(db['ENGINE'])
  File "/home/mycode/p3env/local/lib/python3.5/dist-packages/django/db/utils.py", line 115, in load_backend
    return import_module('%s.base' % backend_name)
  File "/home/mycode/p3env/lib64/python3.5/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "/home/mycode/p3env/local/lib/python3.5/dist-packages/django/db/backends/postgresql/base.py", line 24, in <module>
    raise ImproperlyConfigured("Error loading psycopg2 module: %s" % e)
django.core.exceptions.ImproperlyConfigured: Error loading psycopg2 module: No module named 'psycopg2'

我在 stackoverflow 上的任何地方都沒有發現這個問題。 可能相關的一點，當我瀏覽虛擬環境的目錄時，我注意到 django 安裝在 /home/mycode/p3env/lib/python3.5/dist-packages 而 psysopg2 安裝在 /home/mycode/p3env /lib64/python3.5/dist-packages.

謝謝你的幫助！

Answer 1

正如@dentemm 所建議的：通過將所有 psysopg2 目錄從它們在 lib64 目錄中的當前位置復制到安裝 django 的目錄 /home/mycode/p3env/lib/python3.5/dist-packages 來解決該問題。

Answer 2

卸載然后重新安裝庫真的很有幫助！

(venv)$ pip 卸載 psycopg2

---

(venv)$ pip install psycopg2