django中的模型save()方法是否很懒？
my_model = MyModel() my_model.name = 'Jeff Atwood' my_model.save() # Some code that is independent of my_model... model_id = model_instance.id print (model_id)
解决方法
有一个懒惰的保存没有多大意义,是吗？ Django的
QuerySets很懒,模型的保存方法不是.
来自django来源：
django / db / models / base.py,第424-437行：
def save(self,force_insert=False,force_update=False,using=None):
"""
Saves the current instance. Override this in a subclass if you want to
control the saving process.
The 'force_insert' and 'force_update' parameters can be used to insist
that the "save" must be an sql insert or update (or equivalent for
non-sql backends),respectively. Normally,they should not be set.
"""
if force_insert and force_update:
raise ValueError("Cannot force both insert and updating in \
model saving.")
self.save_base(using=using,force_insert=force_insert,force_update=force_update)
save.alters_data = True
然后,save_base执行繁重的工作(相同的文件,第439-545行)：
... transaction.commit_unless_managed(using=using) ...
在django / db / transaction.py,第167-178行,你会发现：
def commit_unless_managed(using=None):
"""
Commits changes if the system is not in managed transaction mode.
"""
...
附：所有行号都适用于django版本(1,3,’alpha’,0).
