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Question:
Can RowId be used as a permanent record identifier?
Answer:
Short answer: No.
Long answer:
Developers should make absolutely no assumption about a RowId value other than that it is constant during the length of your program session.
The RowID specification does not specify or mandate that RowID is permanent or not permanent, only that it's uniquely identifying a specific record for some reasonable amount of time.
Furthermore, the persistence of RowID, its construction and what it's based on, is a driver implementation detail. Each driver is free to implement RowID any way it sees fit as long as it conforms to the simple rule above. The exact answer for a particular database driver and version may vary. Most DAW drivers, at the moment, may for example use the primary index to derive RowID. This may or may not be true in the future versions of the DAW drivers, and it may or may not be true for all DAW drivers. It may or may not be true with 3rd party drivers, and it may or may not be true in future versions of 3rd party drivers.
So what should a developer do then? If you want to be reasonably database indepent, it's best to not make any kind of assumptions on RowIDs, how they are derived and how persistent they are. The implementation, and exact behavior of RowID, other than stated above, is a driver implementation detail and may change at any time.
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