在运行迁移之前，django 迁移是运行 django tables2 模块的过滤器吗？

Question

我有一个半大型软件。有一次我将 tables2 包含到该项目中并开始使用它。我在 filter.py 文件中包含了一些基本的模型过滤。现在，如果我删除我的数据库并尝试运行新的迁移，我会收到错误消息，即此 table 不可用。我建立了一个 try catch around 并且它正在工作，因为它没有运行迁移之前截断的代码。

class PracticephaseProjectFilter(django_filters.FilterSet):
    omni = django_filters.CharFilter(method=omni_search, label="Suche")
    practice_phase = django_filters.ModelChoiceFilter(queryset=PracticePhase.objects.filter(pk__in=get_pp_for_specialpermit()))

    class Meta:
        model = PracticePhaseProject
        fields = ['practice_phase']

    def __init__(self, *args, **kwargs):
        super(PracticephaseProjectFilter, self).__init__(*args, **kwargs)

def get_pp_for_specialpermit():
    pp = []
    today = date.today()
    # check if SS or WS required
    if 4 <= today.month <= 9:
        # current SS, project will be sought for WS this year
        pp_str = [str(today.year)[-2:] + "s", str(today.year - 1)[-2:] + "w"]
    # we are in WS, check correct year for SS
    elif today.month > 9:
       pp_str = [str(today.year)[-2:] + "w", str(today.year)[-2:] + "s"]
    # we are allready in the year of next SS
    else:
        pp_str = [str(today.year - 1)[-2:] + "s", str(today.year - 1)[-2:] + "w"]
    try:
        for _pp in PracticePhase.objects.filter(semester__name__in=pp_str):
            pp.append(_pp.pk)
    except:
        pass
    return pp

现在，如果我删除围绕 for 循环的 try catch，我将无法运行迁移，因为我遇到数据库错误，没有 table 练习阶段。但在迁移之前不应调用该文件。

Answer 1

makemigrations 和 migrate 命令之前的 system checks framework 运行秒运行。

URL 检查会导致您的 urls.py 被导入，从而加载包含 PracticephaseProjectFilter.

的模块

您不应该在过滤器集定义中调用 get_pp_for_specialpermit - 这意味着查询将在服务器启动时运行一次。这意味着在 Django 服务器准备好之前您有一个不必要的查询，并且结果稍后可能会过时。

您可以通过将查询集移动到 __init__ 方法来阻止查询运行ning:

class PracticephaseProjectFilter(django_filters.FilterSet):
    omni = django_filters.CharFilter(method=omni_search, label="Suche")
    practice_phase = django_filters.ModelChoiceFilter(queryset=PracticePhase.objects.none())

    class Meta:
        model = PracticePhaseProject
        fields = ['practice_phase']

    def __init__(self, *args, **kwargs):
        super(PracticephaseProjectFilter, self).__init__(*args, **kwargs)
        self.filters['practice_phase'].queryset = PracticePhase.objects.filter(pk__in=get_pp_for_specialpermit())

在运行迁移之前，django 迁移是运行 django tables2 模块的过滤器吗？

Is it right that django migrations are running the filter of django tables2 module before running the migrations?

python

django

django-tables2

django-migrations

在 运行 迁移之前，django 迁移是 运行 django tables2 模块的过滤器吗？

Is it right that django migrations are running the filter of django tables2 module before running the migrations?

python

django

django-tables2

django-migrations

在运行迁移之前，django 迁移是运行 django tables2 模块的过滤器吗？