在新模型实例 Django 中使用保存的 ModelForm 作为外键

Question

我正在尝试将保存的 ModelForm 实例的主键作为外键传递给 Django 上的新查询实例。

我不太确定它为什么不起作用。我尝试拆分获取外键 ID，它返回一个数字，但仍然无法正常工作。

任何关于我做错了什么的见解将不胜感激。

Views.py

def customer_inquiry(request):
submitted = False
if request.method == 'POST':
    form = CustomerForm(request.POST)
    if form.is_valid():
        customer = form.save()
        identity = customer.pk
        obj = Customer.objects.get(cust_id=identity)
        inquiry = Inquiry.objects.create(
            cust_id = Customer.objects.get(cust_id = obj.pk),
            inquiry_date = datetime.now)
        return HttpResponseRedirect('/customer_inquiry/?submitted=True')
else:
    form = CustomerForm()
    if 'submitted' in request.GET:
        submitted = True
return render(request, 'customer_inquiry.html', {'form': form, 'submitted': submitted})

Model.py

    inquiry_id = models.AutoField(primary_key=True)
    cust_id = models.ForeignKey(Customer, on_delete=models.CASCADE)
    inquiry_date = models.DateField()

class Inquiry(models.Model):
    inquiry_id = models.AutoField(primary_key=True)
    cust_id = models.ForeignKey(Customer, on_delete=models.CASCADE)
    inquiry_date = models.DateField()

错误

Request Method: POST
Request URL: http://127.0.0.1:8000/customer_inquiry/

Django Version: 3.0.3
Python Version: 3.8.1
Installed Applications:
['database',
 'django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'rest_framework']
Installed Middleware:
['django.middleware.security.SecurityMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.common.CommonMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware']



Traceback (most recent call last):
  File "/Users//.local/share/virtualenvs/-xHaG2iwn/lib/python3.8/site-packages/django/core/handlers/exception.py", line 34, in inner
    response = get_response(request)
  File "/Users//.local/share/virtualenvs/-xHaG2iwn/lib/python3.8/site-packages/django/core/handlers/base.py", line 115, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/Users//.local/share/virtualenvs/-xHaG2iwn/lib/python3.8/site-packages/django/core/handlers/base.py", line 113, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/Users//Code/copy//bikelockerapp/bikelockerapp/views.py", line 17, in customer_inquiry
    inquiry = Inquiry.objects.create(
  File "/Users//.local/share/virtualenvs/-xHaG2iwn/lib/python3.8/site-packages/django/db/models/manager.py", line 82, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/Users//.local/share/virtualenvs/-xHaG2iwn/lib/python3.8/site-packages/django/db/models/query.py", line 433, in create
    obj.save(force_insert=True, using=self.db)
  File "/Users//.local/share/virtualenvs/-xHaG2iwn/lib/python3.8/site-packages/django/db/models/base.py", line 745, in save
    self.save_base(using=using, force_insert=force_insert,
  File "/Users//.local/share/virtualenvs/-xHaG2iwn/lib/python3.8/site-packages/django/db/models/base.py", line 782, in save_base
    updated = self._save_table(
  File "/Users//.local/share/virtualenvs/-xHaG2iwn/lib/python3.8/site-packages/django/db/models/base.py", line 887, in _save_table
    results = self._do_insert(cls._base_manager, using, fields, returning_fields, raw)
  File "/Users//.local/share/virtualenvs/-xHaG2iwn/lib/python3.8/site-packages/django/db/models/base.py", line 924, in _do_insert
    return manager._insert(
  File "/Users//.local/share/virtualenvs/-xHaG2iwn/lib/python3.8/site-packages/django/db/models/manager.py", line 82, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/Users/alessandrolou/.local/share/virtualenvs/CascadeBicycleClubCapstone-xHaG2iwn/lib/python3.8/site-packages/django/db/models/query.py", line 1204, in _insert
    return query.get_compiler(using=using).execute_sql(returning_fields)
  File "/Users//.local/share/virtualenvs/-xHaG2iwn/lib/python3.8/site-packages/django/db/models/sql/compiler.py", line 1383, in execute_sql
    for sql, params in self.as_sql():
  File "/Users//.local/share/virtualenvs/-xHaG2iwn/lib/python3.8/site-packages/django/db/models/sql/compiler.py", line 1326, in as_sql
    value_rows = [
  File "/Users//.local/share/virtualenvs/-xHaG2iwn/lib/python3.8/site-packages/django/db/models/sql/compiler.py", line 1327, in <listcomp>
    [self.prepare_value(field, self.pre_save_val(field, obj)) for field in fields]
  File "/Users//.local/share/virtualenvs/-xHaG2iwn/lib/python3.8/site-packages/django/db/models/sql/compiler.py", line 1327, in <listcomp>
    [self.prepare_value(field, self.pre_save_val(field, obj)) for field in fields]
  File "/Users/alessandrolou/.local/share/virtualenvs/-xHaG2iwn/lib/python3.8/site-packages/django/db/models/sql/compiler.py", line 1268, in prepare_value
    value = field.get_db_prep_save(value, connection=self.connection)
  File "/Users//.local/share/virtualenvs/-xHaG2iwn/lib/python3.8/site-packages/django/db/models/fields/__init__.py", line 821, in get_db_prep_save
    return self.get_db_prep_value(value, connection=connection, prepared=False)
  File "/Users//.local/share/virtualenvs/-xHaG2iwn/lib/python3.8/site-packages/django/db/models/fields/__init__.py", line 1220, in get_db_prep_value
    value = self.get_prep_value(value)
  File "/Users//.local/share/virtualenvs/-xHaG2iwn/lib/python3.8/site-packages/django/db/models/fields/__init__.py", line 1215, in get_prep_value
    return self.to_python(value)
  File "/Users//.local/share/virtualenvs/-xHaG2iwn/lib/python3.8/site-packages/django/db/models/fields/__init__.py", line 1177, in to_python
    parsed = parse_date(value)
  File "/Users//.local/share/virtualenvs/-xHaG2iwn/lib/python3.8/site-packages/django/utils/dateparse.py", line 75, in parse_date
    match = date_re.match(value)

Exception Type: TypeError at /customer_inquiry/
Exception Value: expected string or bytes-like object```

Answer 1

inquiry_date = datetime.now 应改为：inquiry_date = datetime.now()。

这是一个您需要调用才能获取当前日期时间的函数。并且错误指向parse_date 而不是主键。

为了让你的代码更简洁更好：

from datetime import datetime

def customer_inquiry(request):
    submitted = False
    if request.method == 'POST':
        form = CustomerForm(request.POST)
        if form.is_valid():
            customer = form.save()
            # No need for extra database query.
            Inquiry.objects.create(cust_id=customer, inquiry_date=datetime.now())
            return HttpResponseRedirect('/customer_inquiry/?submitted=True')
    else:
        form = CustomerForm()
        if 'submitted' in request.GET:
            submitted = True
    return render(request, 'customer_inquiry.html', {'form': form, 'submitted': submitted})