Thanks Ikai,
I am doing it the way you described and it does work. Just wanted to know if
there is a way to set the child key explicitly as parent + "const string".
But I understood that will not work with datastore generated keys since the
parent needs to be persisted in order to get a key. Apologies for the naive
question :).
Manny

On Fri, Feb 12, 2010 at 1:41 AM, Ikai L (Google) <[email protected]> wrote:

> Are both the parent and child persisted at the same time? If so, you can
> add the child object as a child (not the Key) of the Parent object and call
> makePersistent on the Parent.
>
> On Thu, Feb 4, 2010 at 1:28 AM, Manny S <[email protected]> wrote:
>
>> I am missing something simple here but can anyone point me to how I can
>> set the child key before making the parent data persistent...(in a
>> unidirectional one to one relationship)
>>
>> I create the parent data and the child data
>>
>> parentdata pdata = new parentdata('x','y', 'z');
>> pdata.setKey(null);
>> childdata child = new childdata('A');
>> pdata.setChild(child);
>>
>> Now, I would like to set the child key as parent key + mystring
>>
>> When I try,
>> String strparentKey = KeyFactory.keyToString(pdata.getKey());
>> String strchildKey = strparentKey + "details";
>> Key childKey = KeyFactory.stringToKey(strchildKey);
>>
>> it gives me an error as the parent data does not have a key yet (cause is
>> null)
>>
>> In this case the key of the parent is generated only when I persist. But I
>> need to set the child key before I make it persistent. My application cannot
>> generate an unique app id and I rely on the datastore to do it. As far as I
>> can tell the KeyFactory.Builder does not have an option to generate unique
>> keys and relies on the app to provide it and so I cant use that either.
>>
>> Any help would be appreciated...
>>
>> Manny
>>
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>
>
>
> --
> Ikai Lan
> Developer Programs Engineer, Google App Engine
> http://googleappengine.blogspot.com | http://twitter.com/app_engine
>
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