如何在django中以ModelMultipleChoiceField的形式获得不同的月份和年份？

Question

我有两种模式如下：

class Program(Model):
    name = CharField(...)
    teacher = CharField(...)

class ProgramIntake(Model):
    program = ForeignKey(Program, ...)
    intake = DateField(null=True, blank=True, )

我有几个程序对象，例如数学和艺术作为程序模型的实例：

math = Program.objects.create(name='math', teacher='teacher1')
art = Program.objects.create(name='art', teacher='teacher2')

每个程序都有几个入口：

math_intake1 = PorgramIntake.objects.create(program=math, intake='2019-01-01')
math_intake2 = PorgramIntake.objects.create(program=math, intake='2019-01-15')
math_intake3 = PorgramIntake.objects.create(program=math, intake='2020-01-01')
art_intake1 = PorgramIntake.objects.create(program=art, intake='2019-01-01')
art_intake2 = PorgramIntake.objects.create(program=art, intake='2019-02-18')
art_intake3 = PorgramIntake.objects.create(program=art, intake='2020-05-21')

为了建立我的表格，我建立了这个模型：

class ProgramIntakeEnroll(Model):
    available_intakes = ManyToManyField(ProgramIntake, 
    blank=True, ...)

下面的表格是ModelForm：

class ProgramIntakeEnrollForm(ModelForm):
    available_intakes = ModelMultipleChoiceField(queryset=ProgramIntakeEnroll.objects.values_list('intake', flat=True).distinct().order_by('intake'), required=False)

    class Meta:
        model = ProgramIntakeEnroll
        fields = '__all__'

本人现将此表格提交如下：

def programs(request):
    template_name = 'programs/programs.html'
    context = {}

    if request.POST:
        program_intake_enroll_form = ProgramIntakeEnrollForm(request.POST)
        if study_intake_form.is_valid():
            pass

    else:
        program_intake_enroll_form = ProgramIntakeEnrollForm()

    context.update({'program_intake_enroll_form': program_intake_enroll_form,})
 return render(request, template_name, context)

在html中，我有：

<form method="post">
{% csrf_token %}
    {{ program_intake_enroll_form.as_p }}
<button type="submit">Filter</button>
</form>

我所期望的是，我只想看到以下的选择：

2019年1月

2019年2月

2020年1月

2020年5月

我想我必须更改我的ModelForm中的查询集，但是我不知道如何更改它。

Answer 1

我改变了模型如下，它现在正在工作：

class IntakeRound(Model):
    intake_year = PositiveSmallIntegerField(blank=True, null=True)
    intake_month = PositiveSmallIntegerField(blank=True, null=True)

    class Meta:
        unique_together = ('intake_year', 'intake_month',)

    def __str__(self):
        return str(self.intake_year) + '-' + str(self.intake_month)


class Program(Model):
    name = CharField(...)
    intake = ManyToManyField(IntakeRound, through='ProgramIntake', blank=True)


class ProgramIntake(Model):
    program = ForeignKey(Program, on_delete=CASCADE, related_name='program_intakes')
    program_intake_round = ForeignKey(IntakeRound, on_delete=CASCADE, related_name='program_intakes')
    program_start_date = DateField(null=True, blank=True, verbose_name='Program Start Date')
    program_submission_deadline = DateField(null=True, blank=True, verbose_name='Program Submission Deadline')

    class Meta:
        ordering = ('program_start_date',)

    def __str__(self):
        return str(self.program) + '-' + str(self.program_intake_round)

为了能够使用ModelForm，为了分离数据库中可用的程序和学生的兴趣，这里我也有这个模型。请注意，我不想填充它。在这个阶段，我刚刚构建了一个ModelForm：

class ProfileStudyInterest(Model):
    intake_rounds_of_interest = ManyToManyField(IntakeRound, blank=True, verbose_name='Intake Rounds')

这是我的表格：

class ProfileInterestFilterForm(ModelForm):
    intake_rounds_of_interest = ModelMultipleChoiceField(queryset=IntakeRound.objects.all(), required=False)

    class Meta:
        model = ProfileStudyInterest
        fields = '__all__'

然而，我感到不舒服的是，我的模型中有program_start_date，而program_intake_round在同一模式下，也就是start_date的月份和年份。我认为从数据库设计的角度来看，这是不正确的或最佳做法。