On Jun 8, 2007, at 7:01 AM, Craig L Russell wrote:
> Just FYI, when JDO reads data from tables without PK, it internally
> creates a unique id, similar to a generated PK, for the objects
> that it reads and these ids are discarded when no longer needed.
> The fact that the mapping is for tables without PK is known by the
> code that creates the temporary ids.
>
> Craig
Hi Craig,
I can probably implement this in Cayenne in about 30 minutes, as
Cayenne has a notion of "temporary id" (normally used for new
uncommitted objects). The problem of course is uniquing. So say if a
DB row is fetched from a table via a query, resulting in object A,
and then later the same row is navigated to via a relationship from
another object, resulting in a second object B, distinct from A. This
breaks the fundamental assumption about object identity. So we chose
not to go this way.
Andrus
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