[CentralOH] (Django) ValueError: 'Book' instance needs to have a primary key value before a many-to-many relationship can be used.
jep200404 at columbus.rr.com
jep200404 at columbus.rr.com
Wed Oct 24 17:06:06 CEST 2012
On Wed, 24 Oct 2012 10:37:30 -0400, Kurtis Mullins <kurtis.mullins at gmail.com> wrote:
> You should only need 1 save. The .add() doesn't require a save if memory
> serves me correctly.
I am dealing with a newly created object/row that does not yet
have a primary key (id) until the first save.
How were you getting a value for the primary key for the .add()
to use? Were you using an object/row that already existed and so
had already been saved earlier?
On Wed, 24 Oct 2012 10:29:03 -0400, jep200404 at columbus.rr.com wrote:
> by doing a .save() to flesh out the primary key value,
> then doing the .add() for the ManyToManyField,
> then doing another .save().
I might have discovered a solution. I see something now that
I did not see when I first looked at the code[1].
Add commit=False to the first save.
[1] busi = business.save(commit=False)
from the last answer of
http://stackoverflow.com/questions/6090859/django-instance-needs-to-have-a-primary-key-value-before-a-many-to-many-relatio
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