Django can't display data from two models - django

Question

I am trying to display data from two different models. The two models have a one-to-many relationship but I am not sure why it is not displaying the data from the MembersPresent model. Here are my models
and view
class fly_minute(models.Model):
mode = (
('Email', 'Email'),
('Zoom', 'Zoom'),
('Alternative', 'Alternative'),
)
mode_of_meeting = models.CharField(max_length=100, choices=mode, blank=False, )
date = models.DateField()
Time = models.TimeField()
minute_prepared_by = models.CharField(max_length=25)
location = models.CharField(max_length=25)
authorize_by = models.CharField(max_length=25)
item = models.TextField()
owner = models.CharField(max_length=25)
def __str__(self):
return self.mode_of_meeting
class MembersPresent(models.Model):
flyminute = models.ForeignKey(fly_minute, on_delete=models.CASCADE)
name = models.CharField(max_length=25)
status = models.CharField(max_length=25)
email = models.EmailField(max_length=25)
phone = models.IntegerField()
def __str__(self):
return self.name
#login_required(login_url='login_page')
def MinutesReport(request, minute_id):
report = fly_minute.objects.filter(id=minute_id)
return render(request, 'minute_report.html', locals())
{%for rpt in report%}
<tbody>
<tr class="table-active">
<td>{{rpt.flyminute.name}}</td>
<td>{{rpt.flyminute.status}}</td>
<td>{{rpt.flyminute.email}}</td>
<td>{{rpt.flyminute.phone}}</td>
</tbody>
{%endfor%}

Answer 1

You need to use 'prefetch_related()'
Returns a QuerySet that will automatically retrieve, in a single batch, related objects for each of the specified lookups.
This has a similar purpose to select_related, in that both are designed to stop the deluge of database queries that is caused by accessing related objects, but the strategy is quite different.
models.py
class MembersPresent(models.Model):
flyminute = models.ForeignKey(
fly_minute,
related_name='memberspresent_set', # this will be the default name, incase of need of change provide a new one
on_delete=models.CASCADE
)
...
views.py
#login_required(login_url='login_page')
def MinutesReport(request, minute_id):
report = fly_minute.objects.filter(id=minute_id).prefetch_related('memberpresent_set')
return render(request, 'minute_report.html', locals())
For further control, you can use Prefetch along with prefetch_related()
Note:
locals() returns a dict of all the locally defined variables in the current scope and this may result in exposing sensitive info. Instead of that create a custom dict and return it.
...
context = {
'report': report,
...
}
return render(request, 'minute_report.html', context)

Answer 2

You are referencing and querying in the opposite way. Your fly_minute model doesn't contain MembersPresent model as the Foreign Key. You are filtering the fly_minute model and trying to access MembersPresent model. So, you should change your fly_minute to in this way:
class fly_minute(models.Model):
mode = (
('Email', 'Email'),
('Zoom', 'Zoom'),
('Alternative', 'Alternative'),
)
mode_of_meeting = models.CharField(max_length=100, choices=mode, blank=False, )
date = models.DateField()
Time = models.TimeField()
minute_prepared_by = models.CharField(max_length=25)
location = models.CharField(max_length=25)
authorize_by = models.CharField(max_length=25)
item = models.TextField()
owner = models.CharField(max_length=25)
member = models.ForeignKey(MembersPresent, on_delete=models.CASCADE)#add this line and remove fly_minute in MembersPresent model
def __str__(self):
return self.mode_of_meeting
Then in template file change it to in this way:
{%for rpt in report%}
<tbody>
<tr class="table-active">
<td>{{rpt.member.name}}</td>
<td>{{rpt.member.status}}</td>
<td>{{rpt.member.email}}</td>
<td>{{rpt.member.phone}}</td>
</tbody>
{%endfor%}
I guess it works

Answer 3

Thanks, I ended up using fetch-related and had to make adjustments to my template.
<tr>
<th>Name</th>
<th>Status</th>
<th>Email</th>
<th>Phone</th>
</tr>
</thead>
{%for rpt in report%}
{%for rpts in rpt.memberspresent_set.all%}
<tbody>
<tr class="table-active">
<td>{{rpts.name}}</td>
<td>{{rpts.status}}</td>
<td>{{rpts.email}}</td>
<td>{{rpts.phone}}</td>
</tbody>
{%endfor%}
{%endfor%}