我正在尝试以编程方式创建一堆数据库对象，并使用以下代码将其自动保存到数据库中。但是由于某种原因，当我尝试保存对象（即投标对象）时，出现以下错误。在save_tender_to_db（）函数中，触发错误的行是bid_obj.save（）。是什么引起了这个问题？
Traceback (most recent call last):
File "manage.py", line 22, in <module>
execute_from_command_line(sys.argv)
File "C:\Users\ACER\AppData\Local\Programs\Python\Python36\lib\site-packages\django\core\management\__init__.py", line 381, in execute_from_command_line
utility.execute()
File "C:\Users\ACER\AppData\Local\Programs\Python\Python36\lib\site-packages\django\core\management\__init__.py", line 375, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "C:\Users\ACER\AppData\Local\Programs\Python\Python36\lib\site-packages\django\core\management\base.py", line 316, in run_from_argv
self.execute(*args, **cmd_options)
File "C:\Users\ACER\AppData\Local\Programs\Python\Python36\lib\site-packages\django\core\management\base.py", line 353, in execute
output = self.handle(*args, **options)
File "C:\PROJECTS\leadshub\tender_matching_engine\management\commands\scrap_etenders.py", line 8, in handle
main()
File "C:\PROJECTS\leadshub\Tender_Loader\etenders_scraper.py", line 52, in main
save_tender_to_db(entry)
File "C:\PROJECTS\leadshub\Tender_Loader\etenders_scraper.py", line 129, in save_tender_to_db
description=container_tag[0]
File "C:\Users\ACER\AppData\Local\Programs\Python\Python36\lib\site-packages\django\db\models\manager.py", line 82, in manager_method
return getattr(self.get_queryset(), name)(*args, **kwargs)
File "C:\Users\ACER\AppData\Local\Programs\Python\Python36\lib\site-packages\django\db\models\query.py", line 413, in create
obj.save(force_insert=True, using=self.db)
File "C:\Users\ACER\AppData\Local\Programs\Python\Python36\lib\site-packages\django\db\models\base.py", line 718, in save
force_update=force_update, update_fields=update_fields)
File "C:\Users\ACER\AppData\Local\Programs\Python\Python36\lib\site-packages\django\db\models\base.py", line 748, in save_base
updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields)
File "C:\Users\ACER\AppData\Local\Programs\Python\Python36\lib\site-packages\django\db\models\base.py", line 831, in _save_table
result = self._do_insert(cls._base_manager, using, fields, update_pk, raw)
File "C:\Users\ACER\AppData\Local\Programs\Python\Python36\lib\site-packages\django\db\models\base.py", line 869, in _do_insert
using=using, raw=raw)
File "C:\Users\ACER\AppData\Local\Programs\Python\Python36\lib\site-packages\django\db\models\manager.py", line 82, in manager_method
return getattr(self.get_queryset(), name)(*args, **kwargs)
File "C:\Users\ACER\AppData\Local\Programs\Python\Python36\lib\site-packages\django\db\models\query.py", line 1136, in _insert
return query.get_compiler(using=using).execute_sql(return_id)
File "C:\Users\ACER\AppData\Local\Programs\Python\Python36\lib\site-packages\django\db\models\sql\compiler.py", line 1288, in execute_sql
for sql, params in self.as_sql():
File "C:\Users\ACER\AppData\Local\Programs\Python\Python36\lib\site-packages\django\db\models\sql\compiler.py", line 1241, in as_sql
for obj in self.query.objs
File "C:\Users\ACER\AppData\Local\Programs\Python\Python36\lib\site-packages\django\db\models\sql\compiler.py", line 1241, in <listcomp>
for obj in self.query.objs
File "C:\Users\ACER\AppData\Local\Programs\Python\Python36\lib\site-packages\django\db\models\sql\compiler.py", line 1240, in <listcomp>
[self.prepare_value(field, self.pre_save_val(field, obj)) for field in fields]
File "C:\Users\ACER\AppData\Local\Programs\Python\Python36\lib\site-packages\django\db\models\sql\compiler.py", line 1168, in prepare_value
value = value.resolve_expression(self.query, allow_joins=False, for_save=True)
TypeError: 'NoneType' object is not callable
请在下面查看我的代码。
#This is the model that stores the tender.
class Tender(models.Model):
tenderCategory = models.ManyToManyField(Category, blank=False) #this field holds the tender category, e.g. construction, engineering, human resources etc.
tenderProvince = models.ManyToManyField(Province, blank=False) #this is the province the tender was advertised from.
buyersName = models.CharField(max_length=100) #this is the name of the Buyer e.g. Dept. of Transport, Transnet, Dept of Agriculture etc.
summary = models.TextField(blank=False) #this is the tender title as per the Buyer.
refNum = models.CharField(max_length=100) #tender ref number as per the Buyer.
issueDate = models.DateTimeField(blank=True, null=True) #date the tender was published
closingDate = models.DateTimeField(default=timezone.now, blank=True, null=True) #tender closing date
siteInspectionDate = models.DateTimeField(blank=True, null=True)
siteInspection = RichTextField(blank=True, null=True) #site inspection date, if any
enquiries = RichTextField(blank=True, null=True) #this field stores details of the contact person, for the tender.
description = RichTextField(blank=True, null=True) #this is the body of the tender. the tender details are captured here.
assigned_keywords = models.ManyToManyField(Keywords, blank=True)
matched = models.BooleanField(default=False, blank=False)
capture_date = models.DateField(default=timezone.now, blank=False, null=False)
date_assigned = models.DateField(blank=True, null=True)
tDocLinks = RichTextField(blank=True)
def check_if_expired(self):
if self.closingDate < timezone.now():
return True
else:
return False
class Meta:
ordering = ['-closingDate']
def save_tender_to_db(data_rec_str):
try:
url_data_ls = data_rec_str.split(';')
sauce_2 = urllib.request.urlopen('http://www.etenders.gov.za{}'.format(url_data_ls[0]))
soup_2 = BeautifulSoup(sauce_2, 'html.parser')
# finds the container div in the html.
container_tag = soup_2.findAll('div', {'class': 'fieldset-wrapper'})
if len(container_tag) == 1:
tender_obj = Tender(
# tenderCategory=Category.objects.get(pk=1),
# tenderProvince=Province.objects.get(pk=1),
summary=url_data_ls[5].strip(),
refNum=url_data_ls[1].strip(),
issueDate=extract_date(url_data_ls[3].strip(), 2),
description=container_tag[0],
matched=False,
capture_date=timezone.now
)
tender_obj.save() #this is the line that triggers the error
else:
tender_obj = Tender(
# tenderCategory=Category.objects.get(pk=1),
# tenderProvince=Province.objects.get(pk=1),
summary=url_data_ls[5].strip(),
refNum=url_data_ls[1].strip(),
issueDate=extract_date(url_data_ls[2].strip(), 1),
closingDate=extract_date(url_data_ls[3], 2),
siteInspectionDate=extract_date(url_data_ls[4], 2),
description=container_tag[0],
tDocLinks = container_tag[1],
matched=False,
capture_date=timezone.now
)
tender_obj.save() #this is the line that triggers the error
except urllib.error.URLError as e:
print(e)
最后，当我取消注释以下两行时，我得到了随后的错误。我该怎么解决？
# tenderCategory=Category.objects.get(pk=1),
# tenderProvince=Province.objects.get(pk=1),
TypeError: Direct assignment to the forward side of a many-to-many set is prohibited. Use tenderCategory.set() instead.