Aligning migrated models

The model alignment tool aligns migrated Eclipse Modeling Framework (EMF) models, such as EMX models.
You typically use the model alignment tool when one of the following scenarios occurs:
  • You migrate multiple parallel streams that contain variations of the same set of models, which creates many unnecessary differences that you must remove by realigning the model element identifiers. After you complete the alignment, only legitimate differences remain between the two streams of migrated models.
  • You perform multiple migrations of the same stream of models. This situation can occur when you upgrade tools over a period of time. The original models continue to evolve and the new migrated models begin to evolve. Periodically, you must migrate the original model set and align it with the previously migrated model set before you can merge changes from both model sets.

You do not need to use the model alignment tool if you only migrate a single stream of models.

The model alignment tool only aligns models that retain the same overall structure. If you often refactor models in a later stream, you cannot align them. You must propogate any refactoring and partitioning into all related streams before you perform a model migration and alignment.

The model alignment tool runs in multiple stages: it creates a database of identifiers and then continuously updates the database. After a migration, you can align a hierarchy of successive generations of streams. For example, you can align an Enterprise stream with child streams that represent a line of business and projects.

You can also place the database of identifiers under source control, so that you can use it for subsequent migrations. When you align models that are under source control, you must also check out the initial set of migrated models that you use to create the identifier database, because the alignment tool also aligns their model elements.


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