Owner scope versioning

Another flexible way of creating versions is creating owner scope versions. Owner scopes are global instances (instance owner scope). Owner scope versions can be created in order to preserve the state for a global instance and all the instances recursively owned by the instance or for root extents and its subsets. Versions are consistent within the owner scope. Considering relationships to other global instances, consistency is guaranteed for the current version, only, but not for history.

Older owner scope versions are consistent considering owning references and relationships, but may become inconsistent concerning relationships to other owner scopes. Using owner scope versions, no versions are created for extents, i.e. extent indexes always reflect the current collection of referenced instances with current key values. Only, when combining owner scope versioning with managed versioning, extent versions are created for major versions.

Owner scope versioning allows creating new versions for an owner scope whenever required. Owner scopeversions are not timestamped, but in case of instance owner scope one may refer to the instance timestamp in order to locate an instance version by date/time (supposed that the global instance (owner) inherits from system type __OBJECT).

Owner scope versioning is supported as simple owner scope versioning (owner) and as managed owner scope versioning (managedOwner), but also in combination with synchronized (synchronizedOwner, managedSynchronizedOwner)

Simple owner scope versioning allows creating up to 4,294,967,295 versions for each owner scope. In this case, major versions are not created, but the two high order bytes of the version number are formally interpreted as major version number. When combining owner scope versioning with managed versioning, for each major version up to 65,535 minor versions may be created for an owner scope. Minor version numbers are not associated with time stamps.

Relationships to other instance owner scopes (global instances) refer to the current state of those instances. The relationship collection belongs to the instance owner scope and will create proper versions, but changes in related instances are not always reflected properly. One may reduce formal consistency problems by using fixed (unchangeable) keys for such relationships and by not deleting related global instances.