Django重复输入错误（1062）的原因？

我更新了下面的信息以引用给我相同错误的不同模型/视图。它是一个更简单的模型，因此需要考虑的变量更少......

我有以下模型：

class Imaging_order(Order):
    order_description = models.ForeignKey(Imaging_test, limit_choices_to = {'active': 1}, null=True, blank=True)
    orders = models.ManyToManyField(Imaging_test, limit_choices_to = {'active': 1}, related_name='orders')
    ...

我有以下视图（基本上是基于通用 django 类的更新视图，其中混合了几个自定义函数）：

class LoginRequiredMixin(object):
    @method_decorator(login_required)
    def dispatch(self, *args, **kwargs):
        return super(LoginRequiredMixin, self).dispatch(*args, **kwargs)

class EditMixin(object):
    def form_valid(self, form):
        messages.success(self.request, "This %s has been updated." % (self.model._meta.verbose_name), extra_tags='msg')
        return super(EditMixin, self).form_valid(form)

class ImagingMixin(LoginRequiredMixin):
    model = Imaging_order
    form_class = ImagingForm

class ImagingUpdateView(ImagingMixin, EditMixin, UpdateView):
    pass

在我们的实时版本中，我偶尔会收到此错误的通知：

    Traceback (most recent call last):

  File "/home/cpcadmin/webapps/cpcdj2/lib/python2.7/django/core/handlers/base.py", line 111, in get_response
    response = callback(request, *callback_args, **callback_kwargs)

  File "/home/cpcadmin/webapps/cpcdj2/lib/python2.7/django/views/generic/base.py", line 47, in view
    return self.dispatch(request, *args, **kwargs)

  File "/home/cpcadmin/webapps/cpcdj2/lib/python2.7/django/utils/decorators.py", line 28, in _wrapper
    return bound_func(*args, **kwargs)

  File "/home/cpcadmin/webapps/cpcdj2/lib/python2.7/django/contrib/auth/decorators.py", line 23, in _wrapped_view
    return view_func(request, *args, **kwargs)

  File "/home/cpcadmin/webapps/cpcdj2/lib/python2.7/django/utils/decorators.py", line 24, in bound_func
    return func(self, *args2, **kwargs2)

  File "/home/cpcadmin/webapps/cpcdj2/cpc/emr/views.py", line 150, in dispatch
    return super(LoginRequiredMixin, self).dispatch(*args, **kwargs)

  File "/home/cpcadmin/webapps/cpcdj2/lib/python2.7/django/views/generic/base.py", line 68, in dispatch
    return handler(request, *args, **kwargs)

  File "/home/cpcadmin/webapps/cpcdj2/lib/python2.7/django/views/generic/edit.py", line 195, in post
    return super(BaseUpdateView, self).post(request, *args, **kwargs)

  File "/home/cpcadmin/webapps/cpcdj2/lib/python2.7/django/views/generic/edit.py", line 138, in post
    return self.form_valid(form)

  File "/home/cpcadmin/webapps/cpcdj2/cpc/emr/views.py", line 155, in form_valid
    return super(EditMixin, self).form_valid(form)

  File "/home/cpcadmin/webapps/cpcdj2/lib/python2.7/django/views/generic/edit.py", line 112, in form_valid
    self.object = form.save()

  File "/home/cpcadmin/webapps/cpcdj2/lib/python2.7/django/forms/models.py", line 363, in save
    fail_message, commit, construct=False)

  File "/home/cpcadmin/webapps/cpcdj2/lib/python2.7/django/forms/models.py", line 86, in save_instance
    save_m2m()

  File "/home/cpcadmin/webapps/cpcdj2/lib/python2.7/django/forms/models.py", line 82, in save_m2m
    f.save_form_data(instance, cleaned_data[f.name])

  File "/home/cpcadmin/webapps/cpcdj2/lib/python2.7/django/db/models/fields/related.py", line 1149, in save_form_data
    setattr(instance, self.attname, data)

  File "/home/cpcadmin/webapps/cpcdj2/lib/python2.7/django/db/models/fields/related.py", line 746, in __set__
    manager.add(*value)

  File "/home/cpcadmin/webapps/cpcdj2/lib/python2.7/django/db/models/fields/related.py", line 503, in add
    self._add_items(self.source_field_name, self.target_field_name, *objs)

  File "/home/cpcadmin/webapps/cpcdj2/lib/python2.7/django/db/models/fields/related.py", line 587, in _add_items
    '%s_id' % target_field_name: obj_id,

  File "/home/cpcadmin/webapps/cpcdj2/lib/python2.7/django/db/models/query.py", line 360, in create
    obj.save(force_insert=True, using=self.db)

  File "/home/cpcadmin/webapps/cpcdj2/lib/python2.7/django/db/models/base.py", line 460, in save
    self.save_base(using=using, force_insert=force_insert, force_update=force_update)

  File "/home/cpcadmin/webapps/cpcdj2/lib/python2.7/django/db/models/base.py", line 553, in save_base
    result = manager._insert(values, return_id=update_pk, using=using)

  File "/home/cpcadmin/webapps/cpcdj2/lib/python2.7/django/db/models/manager.py", line 195, in _insert
    return insert_query(self.model, values, **kwargs)

  File "/home/cpcadmin/webapps/cpcdj2/lib/python2.7/django/db/models/query.py", line 1436, in insert_query
    return query.get_compiler(using=using).execute_sql(return_id)

  File "/home/cpcadmin/webapps/cpcdj2/lib/python2.7/django/db/models/sql/compiler.py", line 791, in execute_sql
    cursor = super(SQLInsertCompiler, self).execute_sql(None)

  File "/home/cpcadmin/webapps/cpcdj2/lib/python2.7/django/db/models/sql/compiler.py", line 735, in execute_sql
    cursor.execute(sql, params)

  File "/home/cpcadmin/webapps/cpcdj2/lib/python2.7/django/db/backends/mysql/base.py", line 86, in execute
    return self.cursor.execute(query, args)

  File "/usr/local/lib/python2.7/site-packages/MySQLdb/cursors.py", line 174, in execute
    self.errorhandler(self, exc, value)

  File "/usr/local/lib/python2.7/site-packages/MySQLdb/connections.py", line 36, in defaulterrorhandler
    raise errorclass, errorvalue

IntegrityError: (1062, "Duplicate entry '25129-18' for key 2")

我无法判断此错误何时发生（通常此视图工作得很好）。我认为我有一个正常的模型/视图/表单设置，除了我稍微扩展了通用的基于类的视图。我同意下面的评论，即这与 m2m 领域有关。每次出现此错误时，都会调用“save_m2m”，从而导致此错误。我仍然无法重现它。它发生在我的更新页面/视图中，因此我认为只有在使用现有相关记录更新现有模型时才会出现这种情况。这是我能找到的最接近的其他帖子，但没有帮助：IntegrityError：（1062，“键“some_instance_A_id”的重复条目“1830327-1792993””）但没有唯一约束 https://stackoverflow.com/questions/3079890/integrityerror-1062-duplicate-entry-1830327-1792993-for-key-some-instance?rq=1