因此，我有两种不同的django模型，我想根据条件在另一模型（配置为CharField）的一个字段中填充一些字符串，该字符串取决于条件。我为此写了一个简单的方法： method screenshot
def detect_closing_reason(self):
if self.recommendation.stoploss is None:
return 'Non-recognized'
else:
return 'Closing by a stoploss'
在类的下一个方法中，我试图在创建和保存模型实例的内部调用此方法：model creating and saving
def create_virtual_transaction(self):
date = self.recommendation.posted_time
posix_date = datetime.timestamp(date)
vo = VirtualTransaction.objects.create(start_price=self.recommendation.buy_levels,
start_date=posix_date,
end_price=self.recommendation.sell_levels,
end_date=None,
is_closed=None,
author=self.take_author(),
stock=self.recommendation.stock,
coin=self.recommendation.coin,
closing_reason=self.detect_closing_reason()))
vo.save()
通过django管理命令运行此命令时，我收到此错误：error screenshot
Traceback (most recent call last):
File "/home/work/.local/share/virtualenvs/signals-3Fvtwo2f/lib/python3.7/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 21, in <module>
main()
File "manage.py", line 17, in main
execute_from_command_line(sys.argv)
File "/home/work/.local/share/virtualenvs/signals-3Fvtwo2f/lib/python3.7/site-packages/django/core/management/__init__.py", line 381, in execute_from_command_line
utility.execute()
File "/home/work/.local/share/virtualenvs/signals-3Fvtwo2f/lib/python3.7/site-packages/django/core/management/__init__.py", line 375, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/home/work/.local/share/virtualenvs/signals-3Fvtwo2f/lib/python3.7/site-packages/django/core/management/base.py", line 323, in run_from_argv
self.execute(*args, **cmd_options)
File "/home/work/.local/share/virtualenvs/signals-3Fvtwo2f/lib/python3.7/site-packages/django/core/management/base.py", line 364, in execute
output = self.handle(*args, **options)
File "/home/work/signals/trading_signals/parser/management/commands/add_virtual_transaction.py", line 21, in handle
pc.create_virtual_transaction()
File "/home/work/signals/trading_signals/parser/profit_analysis.py", line 57, in create_virtual_transaction
closing_reason=self.detect_closing_reason())
File "/home/work/.local/share/virtualenvs/signals-3Fvtwo2f/lib/python3.7/site-packages/django/db/models/manager.py", line 82, in manager_method
return getattr(self.get_queryset(), name)(*args, **kwargs)
File "/home/work/.local/share/virtualenvs/signals-3Fvtwo2f/lib/python3.7/site-packages/django/db/models/query.py", line 422, in create
obj.save(force_insert=True, using=self.db)
File "/home/work/.local/share/virtualenvs/signals-3Fvtwo2f/lib/python3.7/site-packages/django/db/models/base.py", line 741, in save
force_update=force_update, update_fields=update_fields)
File "/home/work/.local/share/virtualenvs/signals-3Fvtwo2f/lib/python3.7/site-packages/django/db/models/base.py", line 779, in save_base
force_update, using, update_fields,
File "/home/work/.local/share/virtualenvs/signals-3Fvtwo2f/lib/python3.7/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 "/home/work/.local/share/virtualenvs/signals-3Fvtwo2f/lib/python3.7/site-packages/django/db/models/base.py", line 908, in _do_insert
using=using, raw=raw)
File "/home/work/.local/share/virtualenvs/signals-3Fvtwo2f/lib/python3.7/site-packages/django/db/models/manager.py", line 82, in manager_method
return getattr(self.get_queryset(), name)(*args, **kwargs)
File "/home/work/.local/share/virtualenvs/signals-3Fvtwo2f/lib/python3.7/site-packages/django/db/models/query.py", line 1186, in _insert
return query.get_compiler(using=using).execute_sql(return_id)
File "/home/work/.local/share/virtualenvs/signals-3Fvtwo2f/lib/python3.7/site-packages/django/db/models/sql/compiler.py", line 1334, in execute_sql
for sql, params in self.as_sql():
File "/home/work/.local/share/virtualenvs/signals-3Fvtwo2f/lib/python3.7/site-packages/django/db/models/sql/compiler.py", line 1278, in as_sql
for obj in self.query.objs
File "/home/work/.local/share/virtualenvs/signals-3Fvtwo2f/lib/python3.7/site-packages/django/db/models/sql/compiler.py", line 1278, in <listcomp>
for obj in self.query.objs
File "/home/work/.local/share/virtualenvs/signals-3Fvtwo2f/lib/python3.7/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 "/home/work/.local/share/virtualenvs/signals-3Fvtwo2f/lib/python3.7/site-packages/django/db/models/sql/compiler.py", line 1218, in prepare_value
value = field.get_db_prep_save(value, connection=self.connection)
File "/home/work/.local/share/virtualenvs/signals-3Fvtwo2f/lib/python3.7/site-packages/django/db/models/fields/__init__.py", line 1563, in get_db_prep_save
return connection.ops.adapt_decimalfield_value(self.to_python(value), self.max_digits, self.decimal_places)
File "/home/work/.local/share/virtualenvs/signals-3Fvtwo2f/lib/python3.7/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."]
两个字段（首先在第一个屏幕截图中使用一种方法从另一个模型中获取，第二个我试图将其保存在数据库中）配置为CharField：first field second field
class TelegramRecommendation(models.Model):
channel_name = models.CharField(max_length=2000, blank=True, null=True)
channel_forwarded_name = models.CharField(max_length=2000, blank=True, null=True)
stock = models.CharField(max_length=2000, blank=True, null=True)
coin = models.CharField(max_length=2000, blank=True, null=True)
message = models.TextField(blank=True, null=True)
buy_levels = models.CharField(max_length=2000, blank=True, null=True)
sell_levels = models.CharField(max_length=2000, blank=True, null=True)
posted_time = models.DateTimeField(default=None)
stoploss = models.CharField(max_length=2000, blank=True, null=True)
class Meta:
ordering = ('channel_forwarded_name', 'posted_time')
class VirtualTransaction(models.Model):
author = models.ForeignKey(Recommender, on_delete=models.CASCADE)
stock = models.CharField(max_length=2000, blank=True, null=True)
coin = models.CharField(max_length=2000, blank=True, null=True)
start_date = models.CharField(max_length=2000, blank=True, null=True)
end_date = models.CharField(max_length=2000, blank=True, null=True)
start_price = models.DecimalField(max_digits=16, decimal_places=8, blank=True, null=True)
end_price = models.DecimalField(max_digits=16, decimal_places=8, blank=True, null=True)
is_closed = models.CharField(max_length=2000, blank=True, null=True)
closing_reason = models.CharField(max_length=2000, blank=True, null=True)
我曾尝试重置迁移并删除并创建一个数据库（PostgreSQL 11.4），但并没有帮助。 my 0001_initial.py migration
migrations.CreateModel(
name='TelegramRecommendation',
fields=[
('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
('channel_name', models.CharField(blank=True, max_length=2000)),
('channel_forwarded_name', models.CharField(blank=True, max_length=2000)),
('stock', models.CharField(blank=True, max_length=2000)),
('coin', models.CharField(blank=True, max_length=2000)),
('message', models.TextField(blank=True, null=True)),
('buy_levels', models.CharField(blank=True, max_length=2000)),
('sell_levels', models.CharField(blank=True, max_length=2000)),
('posted_time', models.DateTimeField(default=None)),
('stoploss', models.CharField(blank=True, max_length=2000)),
],
options={
'ordering': ('channel_forwarded_name', 'posted_time'),
},
),
migrations.CreateModel(
name='VirtualTransaction',
fields=[
('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
('stock', models.CharField(blank=True, max_length=2000)),
('coin', models.CharField(blank=True, max_length=2000)),
('start_date', models.CharField(blank=True, max_length=2000)),
('end_date', models.CharField(blank=True, max_length=2000)),
('start_price', models.DecimalField(decimal_places=8, max_digits=16)),
('end_price', models.DecimalField(decimal_places=8, max_digits=16)),
('is_closed', models.CharField(blank=True, max_length=2000)),
('closing_reason', models.CharField(blank=True, max_length=2000)),
('author', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='parser.Recommender')),
我的\ d +表名来自psql table information
我在这里找到了类似的问题，但没有任何帮助，我尝试过：重置迁移，将字符串转换为Decimal内置实例
我在django中没有太多经验，我可以犯一个愚蠢的错误，但是我已经花了大约12个小时来进行故障排除，所以我决定在这里写下一个问题。
答案 0 :(得分：0)
该错误是由模型DecimalField中的2个VirtualTransaction（start_price或end_price）引起的。
看起来错误仅在self.detect_closing_reason()中，因为那是.objects.create()的最后一个参数；该错误实际上是由于DecimalField之一
CharField self.recommendation.buy_levels或self.recommendation.sell_levels之一的内容很可能无法转换为Decimal实例。
此外，在使用方法.objects.create()之后，如果您在.save()调用后未进行任何修改，则无需在返回的对象上调用.objects.create()。
为了更容易发现错误，我建议将代码更改为此：
def create_virtual_transaction(self):
date = self.recommendation.posted_time
posix_date = datetime.timestamp(date)
vo = VirtualTransaction()
vo.start_price = self.recommendation.buy_levels
vo.start_date = posix_date
vo.end_price = self.recommendation.sell_levels
vo.end_date = None
vo.is_closed = None
vo.author = self.take_author()
vo.stock = self.recommendation.stock
vo.coin = self.recommendation.coin
vo.closing_reason = self.detect_closing_reason()
vo.full_clean()
vo.save()
注意对vo.full_clean()的呼叫；该行将引发一条更具体的错误消息，指出导致错误的字段。