从 3 个相互关联的表中获取数据并在模板中显示它们 - django答案

【问题标题】：Getting data from 3 tables that related to each other and displaying them in a template - django从 3 个相互关联的表中获取数据并在模板中显示它们 - django
【发布时间】：2018-02-14 01:36:02
【问题描述】：

我想在我的网站上实施一项调查。我为此创建了 3 个表，下面是每个模型的 sn-p：

class Survey(models.Model):
    klass_id = models.ForeignKey(Klass, verbose_name='class', related_name='s_klass', on_delete=models.CASCADE)
    question = models.CharField(max_length=100, verbose_name='title')
    description = models.CharField(max_length=500, verbose_name='description', blank=True, null=True)
    end_date = models.DateTimeField(verbose_name='end date')


class SurveyOptions(models.Model):
    survey_id = models.ForeignKey(Survey, verbose_name='survey name', related_name='s_id', on_delete=models.CASCADE)
    text = models.CharField(max_length=50, verbose_name='option title')

class SurveyResponse(models.Model):
    option_id = models.ForeignKey(SurveyOptions, verbose_name='option name', related_name='s_option', on_delete=models.CASCADE)
    person_id = models.ForeignKey(Profile, verbose_name='responser', related_name='responser', on_delete=models.CASCADE)
    create_date = models.DateTimeField(verbose_name='date', auto_now_add=True)

用户响应调查后，我想获取调查结果并在模板中显示给用户。我想显示调查问题、调查选项和调查回复（每个选项及其百分比）。

views.py 写什么，模板写什么？

第一个模型中的Klass 指的是一个模型。当我转到与每个Klass 相关的页面时，我必须查看Klass 的所有调查。

Klass 指大学课程。

【问题讨论】：

标签： django django-templates django-views django-orm

【解决方案1】：

我喜欢将与数据有关的所有内容都放入模型中，所以这就是我的方法。请注意，我已经删除了您的 _id，否则您最终会引用 Option.survey_id.id 以获取更令人困惑的 id 或 Option.survey_id.text。

在models.py::

class Survey(models.Model):
    klass = models.ForeignKey(Klass, verbose_name='class', related_name='s_klass', on_delete=models.CASCADE)
    question = models.CharField(max_length=100, verbose_name='title')
    description = models.CharField(max_length=500, verbose_name='description', blank=True, null=True)
    end_date = models.DateTimeField(verbose_name='end date')

    @property
    def options(self):
        return SurveyOptions.objects.filter(survey=self)



class SurveyOptions(models.Model):
    survey = models.ForeignKey(Survey, verbose_name='survey name', related_name='s_id', on_delete=models.CASCADE)
    text = models.CharField(max_length=50, verbose_name='option title')


    @property
    def response_as_pct(self):
        option_responses = SurveyResponse.objects.filter(option = self).count()
        survey_responses = SurveyResponse.objects.filter(option__in = self.survey.options).count()

        # will need to handle edge cases of 0 options or 0 responses and may not want to multiply by 100
        return option_responses/survey_responses * 100

class SurveyResponse(models.Model):
    option = models.ForeignKey(SurveyOptions, verbose_name='option name', related_name='s_option', on_delete=models.CASCADE)
    person = models.ForeignKey(Profile, verbose_name='responser', related_name='responser', on_delete=models.CASCADE)
    create_date = models.DateTimeField(verbose_name='date', auto_now_add=True)

在视图中::

surveys = Survey.objects.all()   or filter as required

render in whatever way passing surveys

在模板中::

{% for survey in surveys %}
      {% for option in survey.options %}
             {{ option.text }} - {{ option.response_as_pct }}
      {% endfor %}
{% endor %}

【讨论】：