We propose to reformulate metadata templates such that they represent events changes that occur within the RTS.
Each metadata template represents an event in a change in the RTS, where an event a change is typically something that happens to a template. We currently recognize three major things changes that happen to a template: insertion into the RTS (essentially creation), invalidation, and re-validation. We describe these events changes below. Also, assignment of an instance unique identifier (IUI) is something that happens in the RTS. Currently, these events changes are captured in A templates. At this time, we do not propose to change how IUI assignments are captured as A templates.
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We propose to remove the E parameter from metadata template specification, and replace it with two parameters: the EV CV parameter for event change type and the EC parameter for error code.
The
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CV parameter
The EV CV parameter may take 3 values, defined as follows. It is a required field in the metadata template.
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The original metadata template specification did not envision the possibility that assertions that templates are in error might themselves be made in error. And thus there was no mechanism to restore templates mistakenly asserted to be in error. Thus the "event change view" has improved the flexibility of RT.
One disadvantage to this approach is that to query "good" data in the RTS, the query must check disjunctively for the values I and R in the EC CV parameter. Alternatively, we could add a flag to the templates themselves that determines whether they are valid. This flag would be set to true upon insertion and revalidation, and to false upon invalidation. The disadvantage to that approach is keeping the flag in synchronization with the information in the metadata templates in the RTS.
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The EC parameter takes the same values as the original E parameter except for the value I (insertion). It is not a required field in the case of a template insertion or revalidation. It would be required for any metadata template with an EV CV parameter with value X.
The
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C parameter
The CRC (change reason) parameter continues to exist as before. However, we replace error correction (XM) with error recognition (XR) as an allowed value.
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We cannot assume either. The remaining question is whether it is worth making the distinction? It would certainly be helpful in the grand scheme of things to capture both, so we could differentiate erroneous beliefs from errors in recording those beliefs, so that we could study them.
Implications for Remainder of Templates
| Parameter | Implication |
|---|---|
| iuid | Now refers to the entity that is initiating the change/event in the RTS. |
| td | Now refers to the time at which the change occurs. |