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python - Django - 在对象创建之前删除自身的变量？

问题描述

考虑这个片段：

if fire_prim is not None:
    print('Fire Primary is definitely not Null, here is proof: {}'.format(fire_prim))
    fire_primary_obj = LifeSafety.objects.create(
        name='Fire Primary', 
        store=store_obj, 
        phone_line=fire_prim, 
        phone_line_provider=an_provider)

我们得到以下输出：

Fire Primary is definitely not Null, here is proof: +16077244546
Traceback (most recent call last):
  File "C:\Python\lib\site-packages\django\db\backends\utils.py", line 85, in _execute
    return self.cursor.execute(sql, params)
  File "C:\Python\lib\site-packages\django\db\backends\sqlite3\base.py", line 298, in execute
    return Database.Cursor.execute(self, query, params)
sqlite3.IntegrityError: NOT NULL constraint failed: stores_lifesafety.phone_line

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "C:\Users\admin-dksc104694\Desktop\Dev\it-database\scripts\data.py", line 246, in update_lifesafety_devices
    fire_primary_obj = LifeSafety.objects.create(name='Fire Primary', store=store_obj, phone_line=fire_prim, phone_line_provider=an_provider)
  File "C:\Python\lib\site-packages\django\db\models\manager.py", line 82, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "C:\Python\lib\site-packages\django\db\models\query.py", line 413, in create
    obj.save(force_insert=True, using=self.db)
  File "C:\Python\lib\site-packages\django\db\models\base.py", line 718, in save
    force_update=force_update, update_fields=update_fields)
  File "C:\Python\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:\Python\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:\Python\lib\site-packages\django\db\models\base.py", line 869, in _do_insert
    using=using, raw=raw)
  File "C:\Python\lib\site-packages\django\db\models\manager.py", line 82, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "C:\Python\lib\site-packages\django\db\models\query.py", line 1136, in _insert
    return query.get_compiler(using=using).execute_sql(return_id)
  File "C:\Python\lib\site-packages\django\db\models\sql\compiler.py", line 1289, in execute_sql
    cursor.execute(sql, params)
  File "C:\Python\lib\site-packages\django\db\backends\utils.py", line 100, in execute
    return super().execute(sql, params)
  File "C:\Python\lib\site-packages\django\db\backends\utils.py", line 68, in execute
    return self._execute_with_wrappers(sql, params, many=False, executor=self._execute)
  File "C:\Python\lib\site-packages\django\db\backends\utils.py", line 77, in _execute_with_wrappers
    return executor(sql, params, many, context)
  File "C:\Python\lib\site-packages\django\db\backends\utils.py", line 85, in _execute
    return self.cursor.execute(sql, params)
  File "C:\Python\lib\site-packages\django\db\utils.py", line 89, in __exit__
    raise dj_exc_value.with_traceback(traceback) from exc_value
  File "C:\Python\lib\site-packages\django\db\backends\utils.py", line 85, in _execute
    return self.cursor.execute(sql, params)
  File "C:\Python\lib\site-packages\django\db\backends\sqlite3\base.py", line 298, in execute
    return Database.Cursor.execute(self, query, params)
django.db.utils.IntegrityError: NOT NULL constraint failed: stores_lifesafety.phone_line

我们可以 100% 确定地看到，在对象创建之前的行，fire_prim其值+16077244546应该作为phone_line，但是在创建时它以某种方式被删除。

这是我的模型供参考：

class LifeSafety(models.Model):
    name = models.CharField(max_length=40, default='unspecified')
    store = models.ForeignKey(Store, null=True, on_delete=models.SET_NULL)
    phone_line = PhoneNumberField()
    phone_line_provider = models.ForeignKey(Provider, null=True, on_delete=models.SET_NULL)
    last_verification = models.DateTimeField(auto_now=True)

    def __str__(self):
        return self.name

前置问题：

问题后：

有趣的是，当我在创建时明确使用该字符串时，该对象确实创建时phone_line填充了该字符串，但我仍然收到错误消息。

输入：

    print('Fire Primary is definitely not Null, here is proof: {}'.format(fire_prim))

    fire_primary_obj = LifeSafety.objects.create(
        name = 'Fire Primary', 
        store = store_obj, 
        phone_line = '+16077244546', 
        phone_line_provider = an_provider
    )

输出与上面的堆栈跟踪相同（只有差异检查器中的名称差异）。

我可以进入管理员并看到它已创建，但我仍然得到NOT NULL constraint异常。

在此处输入图像描述

标签： pythondjangopython-3.xdjango-modelsdjango-2.0

解决方案

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