Denormalization: Use Case
Combination of denormalization options varies depending on design mode of your models.
1. Maintaining stability at the physical level when a modification is applied at the logical level.
Context: a synchronization has already been established between the logical and physical levels. The physical level is in production. A modification must be applied at the logical level, without impact on the physical level.
Recommended denormalization options: transfer of mappings, deletion of source objects.
This use case corresponds to a preventive maintenance-oriented work mode: modifications are carried out by anticipation on the logical level, knowing that the physical level must not be modified until further notice.
Result: after denormalization, mappings are re-established between target logical objects and physical objects. After synchronization, nothing changes at the physical level.
2. Developing the physical level when denormalization is applied at the logical level.
Context: a synchronization has already been established between the logical and physical levels. The physical level is not frozen and must develop as a function of the logical level.
Recommended denormalization options: non-transfer of mappings, deletion of source objects.
This use case favors developments at conceptual level, ignoring impact at the physical level.
Result: after denormalization, target logical objects are without mappings and physical objects corresponding to source logical objects are no longer synchronized. After synchronization, the physical level is updated: the physical objects corresponding to source logical objects (objects existing before denormalization are deleted; new physical objects corresponding to target logical objects (objects created by denormalization) are created.
3. Simplifying logical level development during the development phase.
Context: a synchronization has already been established between the logical and physical levels, or the new physical level has not yet been implemented.
Recommended denormalization options: non-transfer of mappings, non-deletion of source objects.
This use case corresponds to an "incremental" work mode: logical level source objects are unchanged. The model is supplemented by target objects resulting from denormalization. These target objects produce a new section at the physical level and the existing physical section remains stable.
Result: after denormalization, mappings are unchanged. After synchronization, new physical objects corresponding to new logical objects are created; physical objects corresponding to source logical objects are unchanged.
4. Favoring installation of multiple scenarios in development phase.
Context: a synchronization has already been established between the logical and physical levels, several modeling options temporarily coexist for a single physical level.
Recommended denormalization options: transfer of mappings, non-deletion of source objects.
This use case, to be used with care, enables keeping two modeling options at conceptual level that produce a common result at the physical level.
Result: after denormalization, physical objects remain connected to source logical objects and are also connected to target logical objects. After synchronization, objects at the physical level are unchanged.
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