如何使多个连接Django查询

Question

我是Django平台的新手。我有一种情况，我需要在一个页面上显示数据，其中表有多个外键列，如状态，优先级和任务类型。当我保存日期时，它保存外键表中的ID，如StatusTable，PriorityTable和TaskTypeTable 。保存工作正常。但是当我从表中检索日期时，它只提供ID而不是名称。 我怎样才能在Django中实现这一目标？

Modle.py

class StatusTable(models.Model):
    status = models.CharField(max_length=20,default='')
    def __str__(self):
       return self.status

class PriorityTable(models.Model):
    priority = models.CharField(max_length=20,default='')
    def __str__(self):
        return self.priority

class TeamTable(models.Model):
    team = models.CharField(max_length=20,default='')
    def __str__(self):
        return self.team

class TaskTypeTable(models.Model):
    tasktype = models.CharField(max_length=30,default='')
    def __str__(self):
        return self.tasktype

class DatacenterTable(models.Model):
    datacenter = models.CharField(max_length=10,default='')
    def __str__(self):
        return self.datacenter


class TaskMaster(models.Model):
  sid = models.CharField(max_length=3)
  processor = models.ForeignKey(User,null=True)
  tasktype = models.ForeignKey(TaskTypeTable, null=True)
  task_title = models.TextField(null=True)
  task_description = models.TextField(null=True)
  datacenter = models.ForeignKey(DatacenterTable,null=True)
  priority = models.OneToOneField(PriorityTable, null=True)
  status = models.ForeignKey(StatusTable, null=True)
  pid = models.IntegerField(null=True)
  sourceincident = models.URLField(null=True)
  errorincident = models.URLField(null=True)
  processingteam = models.ForeignKey(TeamTable, null=True)
  createddate = models.DateField(("Date"), default=datetime.date.today)
  duedate = models.DateField(("Date"), default=datetime.date.today)
  istaskactive = models.BooleanField(default=True)

forms.py

class CreateTaskMaster(forms.Form):
    sid = forms.CharField(required=False,widget=forms.TextInput(attrs={'class': 'form-control mr-sm-2', 'placeholder': 'SID'}))

    tasktype_query = TaskTypeTable.objects.values_list('tasktype', flat=True).distinct()
    tasktype_query_choices = [('', 'Select TaskType')] + [(region, region) for region in tasktype_query]
    tasktype = forms.ChoiceField(tasktype_query_choices, required=True,widget=forms.Select(attrs={'class': 'form-control'}))

    task_title = forms.CharField(widget=forms.Textarea(attrs={'class': 'form-control mr-sm-2', 'placeholder': 'Task Title', 'rows':4}))

    task_description = forms.CharField(widget=forms.Textarea(attrs={'class': 'form-control mr-sm-2', 'placeholder': 'Task Description', 'rows':4}))

    datacenter_query = DatacenterTable.objects.values_list('datacenter', flat=True).distinct()
    datacenter_query_choices = [('', 'Select datacenter')] + [(region, region) for region in datacenter_query]
    datacenter = forms.ChoiceField(datacenter_query_choices, required=True,widget=forms.Select(attrs={'class': 'form-control'}))

    priority_query = PriorityTable.objects.values_list('priority', flat=True).distinct()
    priority_query_choices = [('', 'Select priority')] + [(region, region) for region in priority_query]
    priority = forms.ChoiceField(priority_query_choices, required=True,widget=forms.Select(attrs={'class': 'form-control'}))

    sourceincident = forms.CharField(widget=forms.TextInput(attrs={'class': 'form-control mr-sm-2', 'placeholder': 'Source Incident URL or NO'}))

    processingteam_query = TeamTable.objects.values_list('team', flat=True).distinct()
    processingteam_query_choices = [('', 'Select processingteam')] + [(region, region) for region in processingteam_query]
    processingteam = forms.ChoiceField(processingteam_query_choices, required=True,widget=forms.Select(attrs={'class': 'form-control'}))

    duedate = forms.DateField(widget=forms.TextInput(attrs={'class': 'form-control mr-sm-2', 'placeholder': 'Due Date'}))

views.py

form = CreateTaskMaster()
task_title = TaskMaster.objects.filter()
my_list = [ model_to_dict(x) for x in task_title]
print(my_list)
print(my_list[1]['sid'])
return render(request, 'task/task.html', {'form': form, 'sid':my_list})

Answer 1

无论何时在模型中使用ForeignKey，都要添加该表的主键以进行记录

实施例

 class TaskMaster(models.Model):
     status = models.ForeignKey(StatusTable, null=True)

 class StatusTable(models.Model):
     status = models.CharField(max_length=20,default='')
     def __str__(self):
        return self.status

当新记录添加到TaskMaster时，状态字段需要StatusTable的实例，但是当您查看数据库时，状态字段只是整数（StatusTable的主键）

如果直接转换TaskMaster做词典，你将获得主键（一个数字），这就是你需要序列化器的原因，但是知道使用这个代码。

my_list = [ model_to_dict(x)['status'] = x.status.status for x in task_title]