python - 如何修复“'查询'对象没有属性'contains_column_references'”
问题描述
当我尝试使用 POST 请求将一些数据插入 mysql 数据库时，我收到一条错误消息，通知我 AttributeError: 'Query' object has no attribute 'contains_column_references'
Internal Server Error: /add_borrow/
Traceback (most recent call last):
File "D:\pyvenv\pyvenv\lib\site-packages\django\core\handlers\exception.py", line 34, in inner
response = get_response(request)
File "D:\pyvenv\pyvenv\lib\site-packages\django\core\handlers\base.py", line 115, in _get_response
response = self.process_exception_by_middleware(e, request)
File "D:\pyvenv\pyvenv\lib\site-packages\django\core\handlers\base.py", line 113, in _get_response
response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "D:\Python_workspace\dms\app01\views.py", line 23, in inner
return func(req, *args, **kwargs)
File "D:\Python_workspace\dms\app01\views.py", line 286, in add_borrow
end_time=end_time, number=number, contents=content ,device_id=device)
File "D:\pyvenv\pyvenv\lib\site-packages\django\db\models\manager.py", line 82, in manager_method
return getattr(self.get_queryset(), name)(*args, **kwargs)
File "D:\pyvenv\pyvenv\lib\site-packages\django\db\models\query.py", line 422, in create
obj.save(force_insert=True, using=self.db)
File "D:\pyvenv\pyvenv\lib\site-packages\django\db\models\base.py", line 741, in save
force_update=force_update, update_fields=update_fields)
File "D:\pyvenv\pyvenv\lib\site-packages\django\db\models\base.py", line 779, in save_base
force_update, using, update_fields,
File "D:\pyvenv\pyvenv\lib\site-packages\django\db\models\base.py", line 870, in _save_table
result = self._do_insert(cls._base_manager, using, fields, update_pk, raw)
File "D:\pyvenv\pyvenv\lib\site-packages\django\db\models\base.py", line 908, in _do_insert
using=using, raw=raw)
File "D:\pyvenv\pyvenv\lib\site-packages\django\db\models\manager.py", line 82, in manager_method
return getattr(self.get_queryset(), name)(*args, **kwargs)
File "D:\pyvenv\pyvenv\lib\site-packages\django\db\models\query.py", line 1186, in _insert
return query.get_compiler(using=using).execute_sql(return_id)
File "D:\pyvenv\pyvenv\lib\site-packages\django\db\models\sql\compiler.py", line 1334, in execute_sql
for sql, params in self.as_sql():
File "D:\pyvenv\pyvenv\lib\site-packages\django\db\models\sql\compiler.py", line 1278, in as_sql
for obj in self.query.objs
File "D:\pyvenv\pyvenv\lib\site-packages\django\db\models\sql\compiler.py", line 1278, in <listcomp>
for obj in self.query.objs
File "D:\pyvenv\pyvenv\lib\site-packages\django\db\models\sql\compiler.py", line 1277, in <listcomp>
[self.prepare_value(field, self.pre_save_val(field, obj)) for field in fields]
File "D:\pyvenv\pyvenv\lib\site-packages\django\db\models\sql\compiler.py", line 1208, in prepare_value
if value.contains_column_references:
AttributeError: 'Query' object has no attribute 'contains_column_references'
以下代码获取 POST 请求参数并将其插入数据库
def add_borrow(req):
user_id = req.session.get("user_id")
user_obj = models.Person.objects.filter(id=user_id)
current_time = time.strftime("%Y-%m-%d", time.localtime())
#
if req.method == 'POST':
borrow_name = user_obj[0]
print("--------")
print(user_obj)
print(type(borrow_name.id))
print("*" * 100)
lender_id = req.POST.getlist("person")
lender_name = req.POST.get("pserson")
print("lender_id {} name is {} type is {}".format(lender_id, lender_name, type(lender_id)))
device = req.POST.get("type_id")
number = req.POST.get("number")
content = req.POST.get("contents")
start_time = req.POST.get("start_time")
end_time = req.POST.get("end_time")
# print("content type is {}".format(type(content)))
print("start_time type is {}".format(type(start_time)))
print("device is {} ,device type is {}".format(device, type(device)))
print("number type is {}".format(type(number)))
# 处理device_id
device_id = models.DeviceType.objects.filter(id=device)
# 处理lender_id
lender_last = models.Person.objects.filter(id=lender_id[0])
print("lender_last type is {},".format(lender_last))
print(type(lender_last))
# 处理时间
start_time_new = datetime.datetime.strptime(start_time, "%Y-%m-%d")
end_time_new = datetime.datetime.strptime(end_time, "%Y-%m-%d")
min_time = end_time_new - start_time_new
# 查询库存数量
lender_obj = models.Devices.objects.filter(id=int(lender_id[0]))
print("=" * 120)
print(lender_obj, type(lender_obj))
print("=" * 120)
if number is None:
return HttpResponse('number is null')
if int(number) > lender_obj[0].number:
return HttpResponse("number grater have")
if borrow_name == lender_name:
return HttpResponse('the name is same ')
if contents is None:
return HttpResponse('contents is null')
if min_time.days < 0 or min_time.days > 7:
return HttpResponse('start or end time is wrong')
models.Borrow.objects.create(borrower_id=borrow_name.id, lender_id=lender_last, start_time=start_time,
end_time=end_time, number=number, contents=content ,device_id=device)
# update lender database
"""
edit_device_obj = models.Devices.objects.get(id=new_edit_id)
edit_device_obj.devtype_id = edit_type
edit_device_obj.person_id = edit_person
edit_device_obj.number = edit_number
edit_device_obj.contents = edit_content
edit_device_obj.save()
"""
lender_type_id = lender_obj.devtype_id
# lender_contents = lender_obj.contents
lender_number = lender_obj.number - number
# rewrite lender database
edit_lender_obj = lender_obj
edit_lender_obj.devtype_id = lender_type_id
# edit_lender_obj.contents = lender_contents
edit_lender_obj.number = lender_number
models.Devices.save()
return redirect('/borrow_list/')
person_list = models.Person.objects.all()
devtype_list = models.DeviceType.objects.all()
return render(req, "add_borrow.html", {"person_list": person_list, "devicetype": devtype_list})
ORM 数据库定义如下：
from django.db import models
class Person(models.Model):
id = models.AutoField(primary_key=True)
name = models.CharField(max_length=32, null=False)
password = models.CharField(max_length=128, null=False)
email = models.EmailField(max_length=32, null=False, unique=True)
phone = models.CharField(max_length=11, null=False, unique=True)
def __str__(self):
return self.name
class DeviceType(models.Model):
id = models.AutoField(primary_key=True)
dev_type = models.CharField(max_length=32, null=False)
class Devices(models.Model):
id = models.AutoField(primary_key=True)
number = models.IntegerField()
contents = models.TextField(default=None)
devtype = models.ForeignKey('DeviceType', on_delete=models.CASCADE)
person = models.ForeignKey('Person', on_delete=models.CASCADE)
def __str__(self):
return '{}'.format(self.number)
class Borrow(models.Model):
borrower = models.ForeignKey('Person', related_name='borrower_name', on_delete=models.CASCADE)
lender = models.ForeignKey('Person', related_name='lender_name', on_delete=models.CASCADE)
start_time = models.DateField(auto_now_add=True)
end_time = models.DateField(auto_now_add=True)
number = models.IntegerField()
contents = models.CharField(max_length=256,default=None)
device = models.ForeignKey('Devices', on_delete=models.CASCADE)
def __str__(self):
return 'borrower {} ,lender {}'.format(self.borrower, self.lender)
``
解决方案
尝试将查询集对象添加到 ManyToMany 字段时出现此错误。我这样做是因为我忘记在我的查询集上使用 .first() 来获取单个对象实例。
例如：
first_ford_car = Car.objects.filter(make="Ford")
homeowner.cars.add(first_ford_car)
* where homeowner.cars = models.Many2Many 关系
这导致了我的错误，因为first_ford_car变量是一个查询集而不是单个汽车实例
在我的情况下修复：
first_ford_car = Car.objects.filter(make="Ford").first()
在其他情况下可能会有所不同，但 id 建议在执行 ForeignKey/Many2Many 更新时检查您的类型
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