1) Readable-urls. http://yourapp.appspot.com/users/max versus
http://yourapp.appspot.com/users/192398411324987
2) The datastore doesn't support uniqueness constraints so a user-defined
key is the only way you can do a true createIfNonExistent() method:
beginTxn();
Entity e;
try {
e = lookupByKeyName(keyName);
} cath (EntityNotFoundException enfe) {
e = createNewEntity(keyName);
}
commitTxn();
The final line throws ConcurrentModificationException if someone else
created an entity with the same keyName in between the lookup and the
commit.
Max
On Sun, Feb 21, 2010 at 5:08 PM, DutrowLLC <[email protected]> wrote:
> Hi,
>
> What is the intended purpose of keyName when creating a new Key or new
> Entity in the low-level API? What are the proper use cases for
> keyName?
>
> Thanks!
>
> Chris
>
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