Question

A正在创建一个页面，该页面将从mysql数据库中获取数据。当我尝试获取数据时，我得到了错误。

forms.py

class LeaveTrackerForm(forms.ModelForm):
    emp_id = forms.CharField(max_length=50)
    track = forms.CharField(max_length=50)
    subtrack = forms.CharField(max_length=50,required=False)

    class Meta:
        model = LeaveTracker
        fields = ('emp_id','track','subtrack')

models.py

class Leaves(models.Model):
    legend = models.CharField(max_length=10, primary_key = True)
    description = models.CharField(max_length=256)
    comments = models.TextField(blank = True)

    def __str__(self):
        return self.legend


class Location(models.Model):
    location = (
    ('Bangalore', 'Bangalore'),
    ('Chennai', 'Chennai'),
    ('Manila', 'Manila'),
    ('Mohali', 'Mohali'),
    ('Pune', 'Pune'),
    ('US', 'US'),
    )
    location = models.CharField(max_length=50, choices= location, primary_key = True)

    def __str__(self):
        return self.location


class Status(models.Model):
    status = (
    ('active', 'Active'),
    ('inactive', 'Inactive'),

    )
    status = models.CharField(max_length=10, choices = status, primary_key=True)

    def __str__(self):
        return self.status

class Employee(models.Model):
    emp_name = models.CharField(max_length=50)
    emp_id = models.IntegerField(primary_key= True, unique = True)
    email = models.EmailField()
    ntid = models.CharField(max_length=15)
    designation = models.CharField(max_length=20)
    track = models.ForeignKey('Team', db_column = 'track', on_delete= models.CASCADE)
    contact = models.CharField(max_length=13)

    def __str__(self):
        return "{}".format(self.emp_id,self.emp_name)


class Team(models.Model):
    track = models.CharField(max_length = 50, primary_key = True)#, primary_key = True
    subtrack = models.CharField(max_length=50)
    offsite_lead = models.CharField(max_length=50)
    onsite_lead = models.CharField(max_length=50)
    status = models.ForeignKey('Status', db_column = 'status', on_delete = models.CASCADE)
    location = models.ForeignKey('Location', db_column = 'location', on_delete = models.CASCADE)

    def __str__(self):
        return self.track


class LeaveTracker(models.Model):
    DAY = (
    ('SUN', 'Sunday'),
    ('MON', 'Monday'),
    ('TUE', 'Tuesday'),
    ('WED', 'Wednesday'),
    ('THU', 'Thursday'),
    ('FRI', 'Friday'),
    ('SAT', 'Saturday'),

    )
    emp_name = models.CharField(max_length = 50)
    emp_id = models.ForeignKey('Employee', db_column = 'emp_id', on_delete= models.CASCADE)
    start_date = models.DateField()
    end_date = models.DateField()
    day = models.CharField(max_length = 10, choices = DAY)
    legend = models.ForeignKey('Leaves', db_column = 'legend', on_delete = models.CASCADE)
    track = models.ForeignKey('Team', db_column = 'track', on_delete = models.CASCADE)
    contact = models.CharField(max_length=12)
    comments = models.TextField(blank = True)
    date = models.DateTimeField(auto_now = True)  # it will show when the data was created in db

    def __str__(self):
        return "{}".format(self.emp_name)

views.py

class LeaveTrackerView(TemplateView):
    template_name = 'molina/leavetracker.html'

    def get(self, request):
        form = LeaveTrackerForm()
        posts = LeaveTracker.objects.all()
        args = {'form': form, 'posts': posts}
        return render(request, self.template_name, args)

    def post(self, request):
        form = LeaveTrackerForm(request.POST)
        if form.is_valid():
            post = form.save(commit=False)
            post.emp_name = request.emp_name
            post.save()
            text = form.cleaned_data['emp_id']
            form = LeaveTrackerForm()
            return redirect('molina:leavetracker')
        args = {'form': form, 'text': text}
        return render(request, self.template_name, args)

leavetracker.html

{% extends 'molina/molina_base.html' %}
{% load bootstrap3 %}
{% block content %}
<body style="background-color:powderblue;">
  <div class = "container">
    <p>Welcome, {{ user.get_username }}</p></div>
     <h1>You are now viewing Leave Tracker</h1>
     <div class="container">
       <form method="post" action= {% url 'molina:leavetracker' %}>
         {% csrf_token %}
         {{ form.as_p }}
       <button type="submit" style="background-color:green;">Submit</button>
       <button type="cancel" style="background-color:green;" name=“cancel” value=“Cancel” >Cancel</button>
       </form>
     </div>
</body>
{% endblock %}

从数据库中获取数据时，出现以下错误 ValueError：无法分配“'656937'”：“ LeaveTracker.emp_id”必须是“ Employee”实例。

Answer 1

永远不要将您的外国字段命名为some_id。 _id后缀表示您正在访问某些数据库层。因此问题出在您的db字段上，仅将其重命名为emp。

emp = models.ForeignKey('Employee', db_column = 'emp', on_delete= models.CASCADE)

ValueError：无法分配“'656937'”：“ LeaveTracker.emp_id”必须是“ Employee”实例

1 个答案: