我有一个模型文件,它使用post_save
信号在另一个表中创建链接行。以典型的方式,我可以从我的一个视图创建一个页面,上面装饰着@transaction.atomic.
我想知道这个装饰器是否会将Page对象和SharedPage对象的创建放在同一个事务中。从django文档中还不清楚信号是这个原子事务的一部分。
型号.py
class Page(models.Model):
name = models.CharField(default='My default page',max_length=200,blank=False)
created_at = models.DateTimeField(auto_now_add=True)
owner = models.ForeignKey(User, on_delete=models.CASCADE)
slug = models.SlugField()
uuid = models.UUIDField(default=uuid.uuid4, editable=False)
is_public = models.BooleanField(default=False)
def __str__(self): # __unicode__ on Python 2
return self.name
class Meta:
ordering = ['position','created_at']
@receiver(post_save, sender=Page)
def create_shared_page_entry(sender, instance, created, **kwargs):
if created:
shared_page = SharedPage.objects.create(
page=instance,
user=instance.user,
can_edit=True
)
view.py
@require_http_methods(["POST"])
@transaction.atomic
def page_create(request):
name = request.POST.get('name')
page = Page.objects.create(name=name, owner=request.user)
data = serializers.serialize("json", [page])
return HttpResponse(data, content_type='application/json')
是的,对于连接的自动提交设置(由transaction.commit decorator进行调整),使用相同的值来调度信号,用于保存模型。引用django.db.models.base.Model.save_base()方法中的代码,
if not meta.auto_created:
signals.pre_save.send(sender=origin, instance=self, raw=raw, using=using, update_fields=update_fields)
with transaction.atomic(using=using, savepoint=False):
if not raw:
self._save_parents(cls, using, update_fields)
updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields)
# Store the database on which the object was saved
self._state.db = using
# Once saved, this is no longer a to-be-added instance.
self._state.adding = False
# Signal that the save is complete
if not meta.auto_created:
signals.post_save.send(sender=origin, instance=self, created=(not updated),update_fields=update_fields, raw=raw, using=using)
正如您所看到的,没有编写任何特殊代码来更改自动提交设置。因此,如果您的视图声明所有与数据库相关的东西都必须通过使用@transaction.atomic来确保原子性,那么在视图执行完成之前,您的视图(model.save()或通过信号处理程序)所做的数据库更改不会被提交。
我希望它能帮助你。