当我运行syncdb它时，它给了我一个MySQL 150错误，可能与 FK 有关。但是，当我反复运行时syncdb，它最终会起作用（下面的整个跟踪）。为什么会出现这种情况？
david-MacBook-Pro$ syncdb
Creating tables ...
Creating table jobs_company
Creating table jobs_job
Traceback (most recent call last):
File "manage.py", line 14, in <module>
execute_manager(settings)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/__init__.py", line 438, in execute_manager
utility.execute()
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/__init__.py", line 379, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/base.py", line 191, in run_from_argv
self.execute(*args, **options.__dict__)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/base.py", line 220, in execute
output = self.handle(*args, **options)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/base.py", line 351, in handle
return self.handle_noargs(**options)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/commands/syncdb.py", line 101, in handle_noargs
cursor.execute(statement)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/backends/util.py", line 34, in execute
return self.cursor.execute(sql, params)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/backends/mysql/base.py", line 86, in execute
return self.cursor.execute(query, args)
File "build/bdist.macosx-10.6-intel/egg/MySQLdb/cursors.py", line 174, in execute
File "build/bdist.macosx-10.6-intel/egg/MySQLdb/connections.py", line 36, in defaulterrorhandler
_mysql_exceptions.OperationalError: (1005, "Can't create table 'david542.#sql-2c3_57e' (errno: 150)")
david-MacBook-Pro:$ syncdb
Creating tables ...
Creating table jobs_jobposition
Creating table jobs_externaljob
Creating table jobs_externalsite
Creating table jobs_sitevisit
Traceback (most recent call last):
File "manage.py", line 14, in <module>
execute_manager(settings)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/__init__.py", line 438, in execute_manager
utility.execute()
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/__init__.py", line 379, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/base.py", line 191, in run_from_argv
self.execute(*args, **options.__dict__)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/base.py", line 220, in execute
output = self.handle(*args, **options)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/base.py", line 351, in handle
return self.handle_noargs(**options)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/commands/syncdb.py", line 101, in handle_noargs
cursor.execute(statement)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/backends/util.py", line 34, in execute
return self.cursor.execute(sql, params)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/backends/mysql/base.py", line 86, in execute
return self.cursor.execute(query, args)
File "build/bdist.macosx-10.6-intel/egg/MySQLdb/cursors.py", line 174, in execute
File "build/bdist.macosx-10.6-intel/egg/MySQLdb/connections.py", line 36, in defaulterrorhandler
_mysql_exceptions.OperationalError: (1005, "Can't create table 'david542.#sql-2c3_57f' (errno: 150)")
david-MacBook-Pro$ syncdb
Creating tables ...
Creating table jobs_application
Traceback (most recent call last):
File "manage.py", line 14, in <module>
execute_manager(settings)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/__init__.py", line 438, in execute_manager
utility.execute()
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/__init__.py", line 379, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/base.py", line 191, in run_from_argv
self.execute(*args, **options.__dict__)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/base.py", line 220, in execute
output = self.handle(*args, **options)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/base.py", line 351, in handle
return self.handle_noargs(**options)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/commands/syncdb.py", line 101, in handle_noargs
cursor.execute(statement)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/backends/util.py", line 34, in execute
return self.cursor.execute(sql, params)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/backends/mysql/base.py", line 86, in execute
return self.cursor.execute(query, args)
File "build/bdist.macosx-10.6-intel/egg/MySQLdb/cursors.py", line 174, in execute
File "build/bdist.macosx-10.6-intel/egg/MySQLdb/connections.py", line 36, in defaulterrorhandler
_mysql_exceptions.OperationalError: (1005, "Can't create table 'david542.#sql-2c3_580' (errno: 150)")
david-MacBook-Pro$ syncdb
Creating tables ...
Installing custom SQL ...
Installing indexes ...
No fixtures found.
它有效吗？