我有一个模型如下
class ExampleModel(models.Model)"
price_one = models.DecimalField(max_digits=6, decimal_places=2, blank=True, null=True)
price_two = models.DecimalField(max_digits=6, decimal_places=2, blank=True, null=True)
我没有ModelForm或只是上述型号的Form，由于某些原因，它显示为html术语如下
<form class="check_foreign_keys" action="." method="post">
.......
.......
<div class="text-field">
<label>Price One(US$)</label>
<div class="input-area">
<input type="text" name="price_one" id="price_one" value="{{ example_model_obj.price_one }}" />
</div>
</div>
<div class="text-field">
<label>Price Two(US$)</label>
<div class="input-area">
<input type="text" name="price_two" id="price_two" value="{{ example_model_obj.price_two }}" />
</div>
</div>
<input type="submit" value="Save Changes" class="fancy-blue-button" />
</form>
Views.py（实施例）
if request.method == 'POST':
obj, created = ExampleModel.objects.get_or_create(price_one=request.POST['price_one'],price_one=request.POST['price_two']......)
obj.save()
错误：
File "/Users/username/.virtualenvs/project/lib/python2.7/site-packages/django/db/models/fields/__init__.py", line 850, in to_python
raise exceptions.ValidationError(msg)
ValidationError: [u"'' value must be a decimal number."]
这里究竟是什么问题，如果没有为price_one和price_two提供任何价值，那么它的价值就是＆＃39;＆＃39;这是我想要的，但作为字段DecimalField它不接受字符串/空值，即使我已在模型中为字段放置null=True和blank=True。
此外，我在google上看到，如果我们使用django.forms.DecimalField，上述错误可能会消失，但我在这里没有使用django表单，只是直接显示html元素。
所以我想要的是取空（＆＃39;＆＃39;）值并保存到数据库，而不会出现上述错误ValidationError: [u"'' value must be a decimal number."]
有谁能让我知道如何解决上述错误？
答案 0 :(得分：0)
我遇到了类似的问题，并相信找到了解决方案。我注意到错误报告有两个部分（见下文）。重要的一行是第6行：
应用store.0005_product_discount_price ...回溯（最近一次调用最后一次）
C:\Users\mnede\PycharmProjects\SeshWebsite\SeshStore\static
Operations to perform:
Apply all migrations: admin, auth, blog, contenttypes, home, sessions, store, taggit, wagtailadmin, wagtailcore, wagtaildocs, wagtailembeds, wagtailforms,
wagtailimages, wagtailredirects, wagtailsearch, wagtailusers
Running migrations:
Applying store.0005_product_discount_price...Traceback (most recent call last):
File "C:\Python\Python36\lib\site-packages\django\db\models\fields\__init__.py", line 1554, in to_python
return decimal.Decimal(value)
decimal.InvalidOperation: [<class 'decimal.ConversionSyntax'>]
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "manage.py", line 12, in <module>
execute_from_command_line(sys.argv)
File "C:\Python\Python36\lib\site-packages\django\core\management\__init__.py", line 367, in execute_from_command_line
utility.execute()
File "C:\Python\Python36\lib\site-packages\django\core\management\__init__.py", line 359, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "C:\Python\Python36\lib\site-packages\django\core\management\base.py", line 294, in run_from_argv
self.execute(*args, **cmd_options)
File "C:\Python\Python36\lib\site-packages\django\core\management\base.py", line 345, in execute
output = self.handle(*args, **options)
File "C:\Python\Python36\lib\site-packages\django\core\management\commands\migrate.py", line 204, in handle
fake_initial=fake_initial,
File "C:\Python\Python36\lib\site-packages\django\db\migrations\executor.py", line 115, in migrate
state = self._migrate_all_forwards(state, plan, full_plan, fake=fake, fake_initial=fake_initial)
File "C:\Python\Python36\lib\site-packages\django\db\migrations\executor.py", line 145, in _migrate_all_forwards
state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)
File "C:\Python\Python36\lib\site-packages\django\db\migrations\executor.py", line 244, in apply_migration
state = migration.apply(state, schema_editor)
File "C:\Python\Python36\lib\site-packages\django\db\migrations\migration.py", line 129, in apply
operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
File "C:\Python\Python36\lib\site-packages\django\db\migrations\operations\fields.py", line 84, in database_forwards
field,
File "C:\Python\Python36\lib\site-packages\django\db\backends\mysql\schema.py", line 43, in add_field
super(DatabaseSchemaEditor, self).add_field(model, field)
File "C:\Python\Python36\lib\site-packages\django\db\backends\base\schema.py", line 395, in add_field
definition, params = self.column_sql(model, field, include_default=True)
File "C:\Python\Python36\lib\site-packages\django\db\backends\base\schema.py", line 147, in column_sql
default_value = self.effective_default(field)
File "C:\Python\Python36\lib\site-packages\django\db\backends\base\schema.py", line 221, in effective_default
default = field.get_db_prep_save(default, self.connection)
File "C:\Python\Python36\lib\site-packages\django\db\models\fields\__init__.py", line 1583, in get_db_prep_save
return connection.ops.adapt_decimalfield_value(self.to_python(value), self.max_digits, self.decimal_places)
File "C:\Python\Python36\lib\site-packages\django\db\models\fields\__init__.py", line 1559, in to_python
params={'value': value},
django.core.exceptions.ValidationError: ["'' value must be a decimal number."]
原来我的model.py字段中没有发生错误，但实际上发生在我的迁移文件中。
根据错误报告，我在迁移文件夹中选择了 0005_product_discount_price.py ，并注意到尝试执行的迁移django仍然包含错误的默认值。
class Migration(migrations.Migration):
dependencies = [
('store', '0004_productpagegalleryimage'),
]
operations = [
migrations.AddField(
model_name='product',
name='discount_price',
field=models.DecimalField(decimal_places=2, default='', max_digits=10),
),
]
我从十进制导入十进制
导入时解决了该问题并更改了我的代码如下：
from __future__ import unicode_literals
from django.db import migrations, models
from decimal import Decimal
class Migration(migrations.Migration):
dependencies = [
('store', '0004_productpagegalleryimage'),
]
operations = [
migrations.AddField(
model_name='product',
name='discount_price',
field=models.DecimalField(decimal_places=2, default=Decimal(0), max_digits=10),
),
]
Django继续尝试执行false语句，导致两个错误报告类似于你自己遇到的错误报告。
希望这有帮助。
ž