Django: join two tables - django

Question

Here's what I currently have:
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")
Now I want to find the Sessions QuerySet which returns ipId=x. Basically this is what I'm trying:
Sessions.objects.filter(affiliation__ip=x)
Is there any way I can do this in django?

Answer 1

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

Answer 2

Refactor your code
Apologize, Please bear with me and learn from it.
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')
Final Model
class ClientSession(models.Model):
client_source = models.ManyToManyField('IP')
class IP(models.Model):
address = models.GenericIPAddressField()
Answer
Querying Session is very straight forward with the current Model.
x = 1 # Some ID
ClientSession.objects.filter(ips__id=x)

Answer 3

I think if you use a related_name in Affiliation model like this:
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"
)
Now you can filter:
Sessions.objects.filter(affiliation_session__ip_id=X)
You can use select_related for optimization if necessary

Answer 4

I want to show a report where I want customer_name, mobile_no, from Details table and status from Status table. You can see my model
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)
Solution
Step1: Add the following code to your view. [views.py]
def customer_report(request):
status_obj = Status.objects.all()
return render('reports/customer_report.html', {'status_obj':status_obj})
Step2: Add the following code at your template side [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>