On Oct 16, 2010, at 2:03 PM, Michael Hipp wrote:
> On 10/16/2010 12:52 PM, Michael Bayer wrote:
>>
>> On Oct 16, 2010, at 1:02 PM, Michael Hipp wrote:
>>
>>> On 8/24/2010 9:47 PM, Michael Bayer wrote:
>>>> Michael Hipp wrote:
>>>>> How do I make a copy of an orm object such that modifications to the
>>>>> copy do not affect the original?
>>>>
>>>> The mapped object has a member "_sa_instance_state" that you basically
>>>> don't want to transfer to your new object. You want it to have its own
>>>> "_sa_instance_state" and this comes from calling the plain constructor,
>>>> which the "copy" module, if that's what you're using, does not use. You
>>>> also want to set attributes normally, not populating __dict__ directly.
>>>> So just basically don't use the "copy" module.
>>>>
>>>> x = MyObject()
>>>> for a in dir(myoldobject):
>>>> if not a.startswith('_'):
>>>> setattr(x, a, getattr(myoldobject, a))
>>>
>>> Resurrecting an old thread ...
>>>
>>> I'm just now getting around to try this but I'm finding out it doesn't
>>> really work like I'd hoped.
>>>
>>> As soon as 'getattr' hits a column with a ForeignKey it immediately tries
>>> to autoflush INSERT 'x'. But 'x' is only half-baked and not ready to be
>>> saved.
>>>
>>> In fact, I don't ever want to save 'x', and I especially don't want to
>>> INSERT it. It would be a duplicate of 'myoldobject'.
>>>
>>> Is there a way to copy an orm object and tell it "don't ever save this I
>>> just want to keep it around to look at"?
>>>
>>> Alternatively I can just copy all the attributes to a dict(), but that's a
>>> bit messy.
>>
>> dont put it in the Session.
>
> That makes sense. But how do I not do that? As in your example code above I'm
> not adding it to a session, at least not intentionally.
don't call Session.add(). the code above doesn't add to a session unless
you're using some special extensions like Session.mapper.
>
> Thanks,
> Michael
>
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