Django：将子查询添加到嵌套模型

Question

我的项目中有以下模型。一个 SRV 包含许多项目，每个项目包含多个任务。我在模板中详细说明每个 SRV，并显示所有相关项目的列表。

class Srv(models.Model):
    srv_year = models.CharField(max_length=4)

class Project(models.Model):
    srv = models.ForeignKey(Srv, on_delete=models.CASCADE, null=True, blank=True)

class Todo(models.Model):
    project = models.ForeignKey(Project, on_delete=models.CASCADE, null=True, blank=True)
    state = models.BooleanField(blank=True, null=True, default=False)

在views.py中我想获取与每个项目关联的已完成任务，但我总是从SRV（主模型）获取与所有项目关联的所有任务

class srvdetail(LoginRequiredMixin, DetailView):
    model = Srv
    template_name = 'srv_detail.html'
    slug_field = 'slug'

更新：

在 Project 模型中添加几个定义，并在模板中打印如下：

class Project(models.Model):
    #...

    def todo_done(self):
        return self.todo_set.filter(state=True).count() * 100 / self.todo_set.all().count()

    def todo_left(self):
        return self.todo_set.filter(state=False).count() * 100 / self.todo_set.all().count()

在我的模板中：

{% for project in srv.project_set.all %}
{{project.todo_done|floatformat:0|intcomma}}% complete
{{project.todo_left|floatformat:0|intcomma}}% left
{% endfor %}

感谢您的 cmets @NKSM

Answer 1

为什么不这样呢？

Todo.objects.filter(
    state = <state>,
    project__srv = <srv_instance>
)

更新：

模板.html：

{% for srv in srvs %}
  <div> srv year: {{srv.srv_year}} </div>
  {% for project in srv.project_set.all %}
    <div> project id: {{project.id}} </div>
    {% for todo in project.todo_set.all %}
      {% if todo.state %}
        <div> todo id: {{todo.id}} </div>
      {% endif %}
    {% endfor %}
  {% endfor %}
{% endfor %}

Answer 2

试试下面的代码：

在你看来：

projects = Project.objects.filter(todo__state=True)

在您的模板中：

<table>
    <tr>
        <th>srv year</th>
        <th>project ID</th>
        <th>Total number of completed tasks</th>
    </tr>
    {% for project in projects %}
    <tr>
        <td>{{ project.srv.srv_year }}</td>
        <td>{{ project.pk }}</td>
        <td>{{ project.todo_set.count }}</td>
    </tr>
    {% enfor %}
</table>