我已经加入了一个致力于Django项目的团队，并且正在尝试设置本地mysql数据库架构。该项目已经存在很长时间了，因此存在现有的迁移。
我已经在mysql中创建了一个空数据库，但是当我尝试应用迁移来创建架构时，它抱怨表还不存在。
$ ./manage.py migrate
Traceback (most recent call last):
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/django/db/backends/utils.py", line 85, in _execute
return self.cursor.execute(sql, params)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/django/db/backends/mysql/base.py", line 71, in execute
return self.cursor.execute(query, args)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/MySQLdb/cursors.py", line 250, in execute
self.errorhandler(self, exc, value)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/MySQLdb/connections.py", line 50, in defaulterrorhandler
raise errorvalue
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/MySQLdb/cursors.py", line 247, in execute
res = self._query(query)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/MySQLdb/cursors.py", line 411, in _query
rowcount = self._do_query(q)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/MySQLdb/cursors.py", line 374, in _do_query
db.query(q)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/MySQLdb/connections.py", line 277, in query
_mysql.connection.query(self, query)
_mysql_exceptions.ProgrammingError: (1146, "Table 'api_test.headset_product' doesn't exist")
我也尝试过syncdb，migrate --run-syncdb和makemigrations，但结果相同。我也尝试过loaddata使用我们的灯具，结果相同。
我已经读过Django : Table doesn't exist，但是在这种情况下我没有删除表（没有表存在过），并且我不想重新创建所有迁移（我不是唯一的人在这个项目上。）
我有一个使用本地Postgresql数据库的相关项目，似乎没有这个问题。我可以运行migrate，它确实可以达到我的期望，所以感觉我遇到了特定于此代码库的问题，但是我们不确定如何调试它。
“ makemigrations的完整输出，包括完整的键入命令。”
$ ./manage.py makemigrations
[WARNING] statsd not configured
[WARNING] SMTP not configured; emails will not be sent
[WARNING] V1 database access not configured
Traceback (most recent call last):
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/django/db/backends/utils.py", line 85, in _execute
return self.cursor.execute(sql, params)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/django/db/backends/mysql/base.py", line 71, in execute
return self.cursor.execute(query, args)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/MySQLdb/cursors.py", line 250, in execute
self.errorhandler(self, exc, value)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/MySQLdb/connections.py", line 50, in defaulterrorhandler
raise errorvalue
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/MySQLdb/cursors.py", line 247, in execute
res = self._query(query)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/MySQLdb/cursors.py", line 411, in _query
rowcount = self._do_query(q)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/MySQLdb/cursors.py", line 374, in _do_query
db.query(q)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/MySQLdb/connections.py", line 277, in query
_mysql.connection.query(self, query)
_mysql_exceptions.ProgrammingError: (1146, "Table 'reign_api_test.headset_product' doesn't exist")
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "./manage.py", line 14, in <module>
execute_from_command_line(sys.argv)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/django/core/management/__init__.py", line 371, in execute_from_command_line
utility.execute()
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/django/core/management/__init__.py", line 365, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/django/core/management/base.py", line 288, in run_from_argv
self.execute(*args, **cmd_options)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/django/core/management/base.py", line 332, in execute
self.check()
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/django/core/management/base.py", line 364, in check
include_deployment_checks=include_deployment_checks,
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/django/core/management/base.py", line 351, in _run_checks
return checks.run_checks(**kwargs)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/django/core/checks/registry.py", line 73, in run_checks
new_errors = check(app_configs=app_configs)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/django/core/checks/urls.py", line 13, in check_url_config
return check_resolver(resolver)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/django/core/checks/urls.py", line 23, in check_resolver
return check_method()
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/django/urls/resolvers.py", line 397, in check
for pattern in self.url_patterns:
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/django/utils/functional.py", line 36, in __get__
res = instance.__dict__[self.name] = self.func(instance)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/django/urls/resolvers.py", line 536, in url_patterns
patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/django/utils/functional.py", line 36, in __get__
res = instance.__dict__[self.name] = self.func(instance)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/django/urls/resolvers.py", line 529, in urlconf_module
return import_module(self.urlconf_name)
File "/Users/rnapier/.pyenv/versions/3.6.6/lib/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 "/Users/rnapier/clients/Jaybird/Source/reign-api/reign_api/reign_api/urls.py", line 13, in <module>
import newsfeed.urls
File "/Users/rnapier/clients/Jaybird/Source/reign-api/reign_api/newsfeed/urls.py", line 2, in <module>
from newsfeed import views
File "/Users/rnapier/clients/Jaybird/Source/reign-api/reign_api/newsfeed/views.py", line 15, in <module>
from newsfeed import models, serializers
File "/Users/rnapier/clients/Jaybird/Source/reign-api/reign_api/newsfeed/serializers.py", line 27, in <module>
class NewsfeedSubscriptionSerializer(serializers.Serializer):
File "/Users/rnapier/clients/Jaybird/Source/reign-api/reign_api/newsfeed/serializers.py", line 28, in NewsfeedSubscriptionSerializer
PRODUCTS = [f for f in headset.models.Product.objects.values_list("name", flat=True)]
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/django/db/models/query.py", line 272, in __iter__
self._fetch_all()
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/django/db/models/query.py", line 1179, in _fetch_all
self._result_cache = list(self._iterable_class(self))
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/django/db/models/query.py", line 178, in __iter__
for row in compiler.results_iter(chunked_fetch=self.chunked_fetch, chunk_size=self.chunk_size):
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/django/db/models/sql/compiler.py", line 1017, in results_iter
results = self.execute_sql(MULTI, chunked_fetch=chunked_fetch, chunk_size=chunk_size)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/django/db/models/sql/compiler.py", line 1066, in execute_sql
cursor.execute(sql, params)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/django/db/backends/utils.py", line 100, in execute
return super().execute(sql, params)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/django/db/backends/utils.py", line 68, in execute
return self._execute_with_wrappers(sql, params, many=False, executor=self._execute)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/django/db/backends/utils.py", line 77, in _execute_with_wrappers
return executor(sql, params, many, context)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/django/db/backends/utils.py", line 85, in _execute
return self.cursor.execute(sql, params)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/django/db/utils.py", line 89, in __exit__
raise dj_exc_value.with_traceback(traceback) from exc_value
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/django/db/backends/utils.py", line 85, in _execute
return self.cursor.execute(sql, params)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/django/db/backends/mysql/base.py", line 71, in execute
return self.cursor.execute(query, args)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/MySQLdb/cursors.py", line 250, in execute
self.errorhandler(self, exc, value)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/MySQLdb/connections.py", line 50, in defaulterrorhandler
raise errorvalue
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/MySQLdb/cursors.py", line 247, in execute
res = self._query(query)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/MySQLdb/cursors.py", line 411, in _query
rowcount = self._do_query(q)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/MySQLdb/cursors.py", line 374, in _do_query
db.query(q)
File "/Users/rnapier/.pyenv/versions/api-3.6.6/lib/python3.6/site-packages/MySQLdb/connections.py", line 277, in query
_mysql.connection.query(self, query)
django.db.utils.ProgrammingError: (1146, "Table 'reign_api_test.headset_product' doesn't exist")
“耳机产品的模型结构”
class Product(models.Model):
"""
products supported by the Headset API
"""
name = models.CharField(max_length=128, unique=True)
def __str__(self) -> str:
return "<Product {s.id} {s.name}>".format(s=self)
__repr__ = __str__
答案 0 :(得分：3)
问题出在reign_api / newsfeed / serializers.py中，它正在尝试在类或模块级别进行查询。在Django中应始终避免这种情况，因为查询将在首次导入时运行-在新系统上的迁移将有机会运行之前。但这也会引起其他问题，因为该查询每个进程只会执行一次，因此在添加或更改新数据时不会更新。
您的同事应该通过重构以将查询移至方法中来解决此问题，或者通过使用更合适的序列化器字段来更好地解决此问题，该序列化器带有一个查询集并在调用时执行查询。