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.
Thanks for all your help,
Michael
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