Django：连接两个表

Question

这是我目前拥有的：

class Sessions(models.Model):
    sessionId = models.AutoField(primary_key=True)

class Ip(models.Model):
    ipId = models.AutoField(primary_key=True)

class Affiliation(models.Model):
    affiliationId = models.AutoField(primary_key=True)
    ip = models.ForeignKey("Ip", null=False, db_column="ipId")
    session = models.ForeignKey("Sessions", null=False, db_column="sessionId")

现在我想找到 returns ipId=x 的 Sessions QuerySet。基本上这就是我正在尝试的：

Sessions.objects.filter(affiliation__ip=x)

有什么方法可以在 django 中做到这一点吗？

Answer 1

重构您的代码

抱歉，请多包涵，吸取教训

You don't have to explicitly specify the id in Django. unless your class is unmanaged. Django automatically use id or pk to refer to it.

class Sessions(models.Model):
    pass

Model naming usually Singular Session.

class Session(models.Model):
    pass

Watch out for conflict model name, Session is already used internally by Django django.contrib.sessions.models.Session. Use alternative name such as ClientSession would be better.

class ClientSession(models.Model):
    pass

Use ManyToManyField (optional), it is just a helper to simplify your queryset.

class ClientSession(models.Model):
    client_source = models.ManyToManyField('IP', through='Affiliation')

Use GenericIPAddressField

class IP(models.Model):
    address = models.GenericIPAddressField()

You have no additional attribute in Affiliation, thus you can consider removing it.

class ClientSession(models.Model):
    client_source = models.ManyToManyField('IP')

最终模型

class ClientSession(models.Model):
    client_source = models.ManyToManyField('IP')

class IP(models.Model):
    address = models.GenericIPAddressField()

回答

Querying Session is very straight forward with the current Model.

x = 1 # Some ID
ClientSession.objects.filter(ips__id=x)

Answer 2

找到答案了！

psobjs = Affiliation.objects.filter(ipId=x)
queryset = Sessions.objects.filter(sessionId__in=psobjs.values('sessionId'))

Answer 3

我想如果你在这样的联盟模型中使用 related_name：

class Sessions(models.Model):
    sessionId = models.AutoField(primary_key=True)

class Ip(models.Model):
    ipId = models.AutoField(primary_key=True)

class Affiliation(models.Model):
    affiliationId = models.AutoField(primary_key=True)
    ip = models.ForeignKey("Ip", null=False, db_column="ipId")
    session = models.ForeignKey(
        "Sessions", null=False, 
        db_column="sessionId", 
        related_name="affiliation_session"
    )

现在您可以过滤：

Sessions.objects.filter(affiliation_session__ip_id=X)

必要时可以使用select_related进行优化

Answer 4

我想在 customer_name、mobile_no、详细信息 table 和状态 table 中显示报告。你可以看到我的模型

class Details(models.Model):
    customer_name = models.CharField(max_length=100,unique=True)
    mobile_no = models.IntegerField()

class Status(models.Model):
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)
    status = models.CharField(max_length=25)
    purchase = models.ForeignKey(Details, null=True, on_delete=models.SET_NULL)

解决方案

第 1 步：将以下代码添加到您的视图中。 [views.py]

def customer_report(request):
    status_obj = Status.objects.all()
    return render('reports/customer_report.html', {'status_obj':status_obj})

第 2 步：在您的模板端添加以下代码 [report.html]

<table class="table">
    <thead>
      <tr>
        <th>Name</th>
        <th>Mobile No</th>
        <th>Status</th>
      </tr>
    </thead>
    <tbody>
        {% for data in status_obj  %}
          <tr>
            <td>{{data.purchase.customer_name}}</td>
            <td>{{data.purchase.mobile_no}}</td>
            <td>{{data.status}}</td>
          </tr>
        {% endfor %}
    </tbody>
</table>

Django：连接两个表

Django: join two tables

django

django-models

重构您的代码

最终模型

回答