> "If an instance has been stored before, the put() method updates the
> existing entity."

As I wrote, Message(handle=handle,owner=person.key())" makes a new
instance.  It's a constructor - it makes a new instance regardless of
what the arguments are.  A new instance, by definition, has not been
stored before.  (No, putting an instance made by calling the
constructor with the same arguments does not change what db.Model
subclass constructors do.  Constructors make new instances.  The only
exception to that rule doesn't apply here.)

If you use key_name and parent, the constructor will make a new
instance with a specific key.  If there is a stored entity with that
key, putting said instance will overwrite the previously stored
entity.

However, that the sentence quoted above does not apply in that
situation because a new instance is not an instance that has been
stored before.


On May 29, 8:51 pm, thebrianschott <[email protected]> wrote:
> Andy,
>
> I am basing my approach on the following sentence at the
> following link.
>
> "If an instance has been stored before, the put() method updates the
> existing entity."
>
> http://code.google.com/appengine/docs/python/datastore/creatinggettin...
>
> What am I missing?
>
> Brian in Atlanta
>
> On May 29, 11:27 pm, Andy Freeman <[email protected]> wrote:
>
>
>
> > > > >         message = Message(handle=handle,owner=person.key())
>
> > That line always creates a new Message instance.  Why do you think
> > that it should do anything else?  (The only way to get copies of
> > existing instances is with get() and queries.)- Hide quoted text -
>
> - Show quoted text -
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