Python Django-按id连接两个查询集？

我试图在发送到视图之前将两个表连接在一起，在视图中使用_set会导致100次查询，这是非常低效的

示例结构sites.models.py

class SiteData(models.Model):
    location = models.CharField(max_length=50)
    site_type = models.ForeignKey(SiteTypes, verbose_name="Site Type", \
                on_delete=models.PROTECT)
    bgp_as = models.CharField(max_length=6, verbose_name="BGP AS Number")
    opening_date = models.DateField(verbose_name="Site opening date")
    last_hw_refresh_date = models.DateField(verbose_name="Date of latest hardware refresh", \
                           blank=True, null=True)
    is_live = models.BooleanField(default=False, verbose_name="Is this a live site?")

class SiteSubnets(models.Model):
    site_data = models.ForeignKey(SiteData, verbose_name="Location", \
                on_delete=models.PROTECT, blank=True, null=True)               
    subnet = models.GenericIPAddressField(protocol='IPv4', \
             verbose_name="Subnet", blank=True, null=True)
    subnet_type = models.ForeignKey(SubnetTypes, verbose_name="Subnet Type") 
    vlan_id = models.IntegerField(verbose_name="Vlan ID", blank=True, null=True)
    peer_desc = models.IntegerField(verbose_name="Peer description", blank=True, null=True)
    site_ip = models.BooleanField(default=False, verbose_name="Is this a site supernet IP?")
    class Meta:
        verbose_name = "Site Subnets"
        verbose_name_plural = "Site Subnets"

示例结构config.models.py

class SiteData(models.Model):
    location = models.CharField(max_length=50)
    site_type = models.ForeignKey(SiteTypes, verbose_name="Site Type", \
                on_delete=models.PROTECT)
    bgp_as = models.CharField(max_length=6, verbose_name="BGP AS Number")
    opening_date = models.DateField(verbose_name="Site opening date")
    last_hw_refresh_date = models.DateField(verbose_name="Date of latest hardware refresh", \
                           blank=True, null=True)
    is_live = models.BooleanField(default=False, verbose_name="Is this a live site?")

class SiteSubnets(models.Model):
    site_data = models.ForeignKey(SiteData, verbose_name="Location", \
                on_delete=models.PROTECT, blank=True, null=True)               
    subnet = models.GenericIPAddressField(protocol='IPv4', \
             verbose_name="Subnet", blank=True, null=True)
    subnet_type = models.ForeignKey(SubnetTypes, verbose_name="Subnet Type") 
    vlan_id = models.IntegerField(verbose_name="Vlan ID", blank=True, null=True)
    peer_desc = models.IntegerField(verbose_name="Peer description", blank=True, null=True)
    site_ip = models.BooleanField(default=False, verbose_name="Is this a site supernet IP?")
    class Meta:
        verbose_name = "Site Subnets"
        verbose_name_plural = "Site Subnets"

查询：

site_subnets = SiteSubnets.objects.only('subnet').filter(site_ip=True)
site_data = SiteData.objects.only('location','is_live','bgp_as','postcode','opening_date','live_link_type')

预期结果示例：

Location   | Subnet     | BGP AS
---------------------------------
London     | 10.10.10.0 | 65001
Manchester | 10.10.20.0 | 65002
...

如果不将sitesubnet表作为主表，我无法执行与select_相关的操作，因为当我对站点数据执行此操作时，我会得到

django.core.exceptions.FieldError: Invalid field name(s) given in select_related: 'site_subnets'. Choices are: site_type

如果我使用SiteSubnet作为主表，如果站点没有SiteSubnet.Site\u up，我将无法获取站点信息。展示

有人知道一种方法可以显示所有数据而不运行n+1查询吗

编辑：

预取也会失败，出现以下错误：

AttributeError: Cannot find 'site_subnets_set' on SiteData object, 'site_subnets_set' is an invalid parameter to prefetch_related()

我会将数据发送到一个模板，以便在循环中访问，即

<table>
  <tr>
    <td>Location</td>
    <td>Subnet</td>
    <td>BGP AS</td>  
  <tr>
{%for site in sitedata %}
  <tr>
    <td>{{ site.location }}</td>
    <td>{{ site.subnet }}</td>
    <td>{{ site.bg_as }}</td>  
  <tr>
{% endfor %}

谢谢

您可以在sitedata queryset中使用与预回迁SiteSubnet相关的预回迁

SiteData.objects.prefetch_related('sitesubnets_set')

---

是否可以使用SiteData.objects.prefetch_相关的“sitesubnets_set”？如果在循环中运行site\u data.sitesubnets\u set.all，则应防止n+1查询。如何显示它？你可以在你的站点子网查询集上做一个for循环，然后从每个元素访问站点数据……你没有尝试我建议的。您使用了site\u subnets\u set而不是sitesubnets\u set。我的错误，这很有效！谢谢你