RFE: add a flag to indicate that a simple observation is a member

[pdowler]

Proposal from HST Archive Coordination Meeting: make it easy to exclude members (SimpleObservation) from search results.

If members could be flagged then the query would not need to include a subquery or join to determine this. In addition, such an on-the-fly approach would mean that composites created by someone else and included in the system (eg in the aggregate database at CADC) would cause simple observations to be hidden. A specific flag would mean the provider that curates the simple and composite observations would control this explicitly.

The form of the flag is TBD.

[pdowler]

Intend to allow any Algorithm.name in SimpleObservation to support normal "exposure" as well as "member" when the simple observation was created with the intent to be a member of a composite. As a side effect, removing restriction on algorithm name would allow for other values like "simulation" (or a specific simulation algorithm) to be used for simple observations.

This is not a model change: just a code/validation change.

To be included in CAOM-2.3

[pdowler]

On further thought, exposure vs member and empirical vs simulation are orthogonal concepts so I would probably recommend against using Algorithm.name for simulated. When we have to support simulated data I will likely add a separate attribute to Algorithm for that, which would allow for simulated simple or composite observations and simulated "member" if someone wanted to do such a thing. This has no effect on the main issue here.

[pdowler]

Constraints on SimpleObservation.algorithm.name removed from the code in CAOM-2.3

The SimpleObservation.ALGORITHM constant (exposure) is retained and the code doesn't allow using it for a CompositeObservation.