我有以下型号：
class Work(models.Model):
title = models.CharField(max_length=30)
amount = models.PositiveIntegerField()
percent = models.FloatField(validators=[MaxValueValidator
(100),MinValueValidator(0)])
drop = models.PositiveIntegerField(default=0)
assignments = models.ManyToManyField(Assignment)
但是当我创造一些“工作”时，它的行为很奇怪：
In [6]: homework = Work("homework",12,15)
In [7]: homework.save()
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
...
#lots and lots of stuff...I will post the extend at the bottom
...
ValueError: invalid literal for int() with base 10: 'homework'
当第一个参数需要CharField时，为什么读取第一个参数应该是int？
我认为我所说的是有道理的。 homework.title应为“家庭作业”，homework.amount应为12，homework.percent应为15，homework.drop应为默认值：0。
有人可以解释为什么会出现这个错误以及我如何解决它。提前谢谢。
In [6]: homework = Work("homework",12,15)
In [7]: homework.save()
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/commands/shell.pyc in <module>()
----> 1 homework.save()
/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/base.pyc in save(self, force_insert, force_update, using, update_fields)
544
545 self.save_base(using=using, force_insert=force_insert,
--> 546 force_update=force_update, update_fields=update_fields)
547 save.alters_data = True
548
/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/base.pyc in save_base(self, raw, cls, origin, force_insert, force_update, using, update_fields)
620 # no force_insert)
621 if ((force_update or update_fields) or (not force_insert and
--> 622 manager.using(using).filter(pk=pk_val).exists())):
623 if force_update or non_pks:
624 values = [(f, None, (raw and getattr(self, f.attname) or f.pre_save(self, False))) for f in non_pks]
/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/query.pyc in filter(self, *args, **kwargs)
665 set.
666 """
--> 667 return self._filter_or_exclude(False, *args, **kwargs)
668
669 def exclude(self, *args, **kwargs):
/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/query.pyc in _filter_or_exclude(self, negate, *args, **kwargs)
683 clone.query.add_q(~Q(*args, **kwargs))
684 else:
--> 685 clone.query.add_q(Q(*args, **kwargs))
686 return clone
687
/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/sql/query.pyc in add_q(self, q_object, used_aliases, force_having)
1257 else:
1258 self.add_filter(child, connector, q_object.negated,
-> 1259 can_reuse=used_aliases, force_having=force_having)
1260 if force_having:
1261 self.having.end_subtree()
/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/sql/query.pyc in add_filter(self, filter_expr, connector, negate, trim, can_reuse, process_extras, force_having)
1188 else:
1189 self.where.add((Constraint(alias, col, field), lookup_type, value),
-> 1190 connector)
1191
1192 if negate:
/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/sql/where.pyc in add(self, data, connector)
69
70 if hasattr(obj, "prepare"):
---> 71 value = obj.prepare(lookup_type, value)
72
73 super(WhereNode, self).add(
/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/sql/where.pyc in prepare(self, lookup_type, value)
337 def prepare(self, lookup_type, value):
338 if self.field:
--> 339 return self.field.get_prep_lookup(lookup_type, value)
340 return value
341
/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/fields/__init__.pyc in get_prep_lookup(self, lookup_type, value)
320 return value
321 elif lookup_type in ('exact', 'gt', 'gte', 'lt', 'lte'):
--> 322 return self.get_prep_value(value)
323 elif lookup_type in ('range', 'in'):
324 return [self.get_prep_value(v) for v in value]
/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/fields/__init__.pyc in get_prep_value(self, value)
553 if value is None:
554 return None
--> 555 return int(value)
556
557 def contribute_to_class(self, cls, name):
ValueError: invalid literal for int() with base 10: 'homework'
答案 0 :(得分：2)
在Work表中创建新记录时，需要使用关键字参数。
homework = Work(title = "homework", amount = 12, drop = 15)
homework.save()
指定参数的顺序无关紧要。如果函数的关键字指定为
def attributes(self, pk='', title='', amount=''):
...
然后你可以在没有关键字的情况下按顺序指定参数。但是，Django模型不会这样做，因为他们无法猜出你的字段名称是什么。他们会实现更多这样的
def attributes(self, **kwargs):
...
其中kwargs将是指定的所有关键字参数的字典。然后，Django模型将根据您传递的任何关键字参数更新数据库。
答案 1 :(得分：0)
第一个参数不应该是int。它应该是一个字段，内容为数字。 Django正在尝试将其转换为int，但由于文本为homework - 这不是有效数字，因此失败。第一个参数应为id，整数或数字字符串。
您必须指定关键字：
homework = Work(title = "homework", amount = 12, drop = 15)
为什么呢？因为默认的第一个参数不是标题或用户定义的任何内容，所以它是id。因此，如果你想跳过id（将由Django自动设置），以及可能还有一些其他生成的参数，你必须指定关键字。
答案 2 :(得分：0)
每个django模型都有一个自动主键，其默认名称为id。在使用Work初始化Work模型（“homework”，12,15）时，您将“homework”字符串传递给id字段。
from product.models import Work
homework = Work("homework",12,15)
print homework.id
#outputs 'homework'
我也找不到django doc中保证Model.__init__ args顺序与字段定义顺序相同的任何单词（由于元类，命令可以不同）。因此，您应该使用名称参数（kwargs）。
答案 3 :(得分：0)
您只需
即可实现此目的Work.objects.create(title="homework", amount=12, drop=15)