Django：我如何从两个模型中对日期进行排序？

Question

1。）我有以下models.py定义：

    from django.db import models
    from datetime import date

    class Author(models.Model):
        author  = models.CharField(max_length=20)
        def __unicode__(self):
            return '%s' % (self.author)

    class SystemA(models.Model):
        author      = models.ForeignKey(Author)
        date        = models.DateField()
        system      = models.CharField(max_length=20, blank=False, default="System A")
        description = models.CharField(max_length=300)
        status = models.CharField(max_length=6)
        def __unicode__(self):
            return '%s, %s, %s, %s, %s' % (self.date, self.author, self.system, self.description, self.status)

    class SystemB(models.Model):
        author      = models.ForeignKey(Author)
        date        = models.DateField()
        system      = models.CharField(max_length=20, blank=False, default="System B")
        description = models.CharField(max_length=300)
        status = models.CharField(max_length=6)
        def __unicode__(self):
            return '%s, %s, %s, %s, %s' % (self.date, self.author, self.system, self.description, self.status)

2。）此admin.py定义：

    from acc.models import SystemA, SystemB, Author
    from django.contrib import admin

    admin.site.register(SystemA)
    admin.site.register(SystemB)

3。）这是我的views.py定义：

    from django.http import HttpResponse
    from acc.models import SystemA, SystemB
    from django.template import Context, loader
    from itertools import chain
    from operator import attrgetter

    def index(request):
      a_list = SystemA.objects.all().order_by('-date')
      b_list = SystemB.objects.all().order_by('-date')
      result_list = sorted(
        chain(a_list, b_list),
        key=attrgetter('date'))
      t = loader.get_template('index.html')
      #c = Context({'result_list': result_list,})
      c = Context({'a_list': a_list,'b_list': b_list,})
      return HttpResponse(t.render(c))

4.）最后，呈现静态HTML页面（index.html）的模板定义为：

    {% if a_list %}
    <ul>
    {% for a in a_list %}
    <li>{{a.date}} | {{a.author}} | {{a.system}} | {{a.description}} | {{a.status}}</li>
    {% endfor %}
    </ul>
    {% endif %}

    {% if b_list %}
    <ul>
    {% for b in b_list %}
    <li>{{b.date}} | {{b.author}} | {{b.system}} | {{b.description}} | {{b.status}}</li>
    {% endfor %}
    </ul>
    {% endif %}

代码正常，我从管理界面输入了一些数据。结果：

April 18, 2013 | owta | System A | All jobs went bananas! | FAILED
April 17, 2013 | rash | System A | All Well | OK

April 18, 2013 | owta | System B | All jobs went bananas! | FAILED
April 17, 2013 | rash | System B | All well | OK

我的目标是按以下排序顺序独立于模型（SystemA / SystemB）获取按日期排序的结果：

April 17, 2013 | rash | System A | All Well | OK
April 17, 2013 | rash | System B | All well | OK
April 18, 2013 | owta | System A | All jobs went bananas! | FAILED
April 18, 2013 | owta | System B | All jobs went bananas! | FAILED

我花了一周的时间试图解决这个问题而没有成功，而且我是Django的菜鸟。一些帮助 非常感谢！感谢。

Answer 1

  

“之前我进入了单模型解决方案，但不知何故觉得我必须为我的系统设置不同的类/模型才能将数据很好地提取到每个系统的日期排序的静态页面中”

好吧，这是你用一种模式做的。请记住，始终尝试减少系统中的重复。

models.py

from django.db import models

class Author(models.Model):
    author  = models.CharField(max_length=20)
    def __unicode__(self):
        return '%s' % (self.author)

class System(models.Model):
    SYSTEM_CHOICES = (('A','System A'),('B','System B'))
    author      = models.ForeignKey(Author)
    date        = models.DateField()
    system      = models.CharField(max_length=1, choices=SYSTEM_CHOICES) # see [1]
    description = models.CharField(max_length=300)
    status      = models.CharField(max_length=6)

admin.py

from django.contrib import admin

class SystemAdmin(admin.ModelAdmin):
    list_filter = ['system'] # See [2]

admin.site.register(System, SystemAdmin)

urls.py

url(r'^/system/(?P<system>A|B)/list/$', views.SystemListView.as_view(), name='system-list' )

views.py

from django.views.generic.list import ListView
from .models import System

class SystemListView(ListView):
    model = System
    context_object_name = "Systems"

    def get_queryset(self):
        return super(SystemListView, self) \
          .filter(system = self.kwargs['system']) \
          .order_by(self.request.GET.get('sort') or '-date')

{template_folder} /yourapp/system/list.html

<h1> System {{ system }}{# See [3] #} </h1>
<ul>
{% for sys in Systems %}
  <li>{{sys.date}} | {{sys.author}} | {{sys.description}} | {{sys.status}}</li>
{% endfor %}
</ul>

附录

[1] https://docs.djangoproject.com/en/stable/ref/models/fields/#choices
[2] https://docs.djangoproject.com/en/stable/ref/contrib/admin/#django.contrib.admin.ModelAdmin.list_filter
[3] https://github.com/django/django/blob/master/django/views/generic/detail.py#L99