已安装pymysql 仍不能连接mariaDB数据库，报错信息为：

$ python manage.py migrate Traceback (most recent call last): File "/usr/local/lib64/python3.6/site-packages/django/db/utils.py", line 111, in load_backend return import_module('%s.base' % backend_name) File "/usr/lib64/python3.6/importlib/init.py", line 126, in import_module return _bootstrap._gcd_import(name[level:], package, level) File "<frozen importlib._bootstrap>", line 994, in _gcd_import File "<frozen importlib._bootstrap>", line 971, in _find_and_load File "<frozen importlib._bootstrap>", line 941, in _find_and_load_unlocked File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed File "<frozen importlib._bootstrap>", line 994, in _gcd_import File "<frozen importlib._bootstrap>", line 971, in _find_and_load File "<frozen importlib._bootstrap>", line 953, in _find_and_load_unlocked ModuleNotFoundError: No module named 'django.db.backends.mysql'

The above exception was the direct cause of the following exception:

Traceback (most recent call last): File "manage.py", line 21, in <module> main() File "manage.py", line 17, in main execute_from_command_line(sys.argv) File "/usr/local/lib64/python3.6/site-packages/django/core/management/init.py", line 401, in execute_from_commande utility.execute() File "/usr/local/lib64/python3.6/site-packages/django/core/management/init.py", line 377, in execute django.setup() File "/usr/local/lib64/python3.6/site-packages/django/init.py", line 24, in setup apps.populate(settings.INSTALLED_APPS) File "/usr/local/lib64/python3.6/site-packages/django/apps/registry.py", line 114, in populate app_config.import_models() File "/usr/local/lib64/python3.6/site-packages/django/apps/config.py", line 211, in import_models self.models_module = import_module(models_module_name) File "/usr/lib64/python3.6/importlib/init.py", line 126, in import_module return _bootstrap._gcd_import(name[level:], package, level) File "<frozen importlib._bootstrap>", line 994, in _gcd_import File "<frozen importlib._bootstrap>", line 971, in _find_and_load File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked File "<frozen importlib._bootstrap>", line 665, in _load_unlocked File "<frozen importlib._bootstrap_external>", line 678, in exec_module File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed File "/usr/local/lib64/python3.6/site-packages/django/contrib/auth/models.py", line 2, in <module> from django.contrib.auth.base_user import AbstractBaseUser, BaseUserManager File "/usr/local/lib64/python3.6/site-packages/django/contrib/auth/base_user.py", line 47, in <module> class AbstractBaseUser(models.Model): File "/usr/local/lib64/python3.6/site-packages/django/db/models/base.py", line 121, in new new_class.add_to_class('_meta', Options(meta, app_label)) File "/usr/local/lib64/python3.6/site-packages/django/db/models/base.py", line 325, in add_to_class value.contribute_to_class(cls, name) File "/usr/local/lib64/python3.6/site-packages/django/db/models/options.py", line 208, in contribute_to_class self.db_table = truncate_name(self.db_table, connection.ops.max_name_length()) File "/usr/local/lib64/python3.6/site-packages/django/db/init.py", line 28, in getattr return getattr(connections[DEFAULT_DB_ALIAS], item) File "/usr/local/lib64/python3.6/site-packages/django/db/utils.py", line 207, in getitem backend = load_backend(db['ENGINE']) File "/usr/local/lib64/python3.6/site-packages/django/db/utils.py", line 126, in load_backend ) from e_user django.core.exceptions.ImproperlyConfigured: 'django.db.backends.mysql' isn't an available database backend. Try using 'django.db.backends.XXX', where XXX is one of: 'oracle', 'postgresql', 'sqlite3'