Overview of migrating data

Migrating data can be useful when you normalize tables and need to move data from one table to another or when you want to copy data between environments. For example, you might want the data in the test environment to closely resemble the data in the production environment.
You can use two different approaches for migrating data from one table to another:

When you migrate data, the data is always saved to external files. Depending on the unload and reload methods that you choose, the data is unloaded to the external files with either Export commands or DB2 High Performance Unload (HPU) and loaded into the target table with Import or Load commands.

When you migrate data to a table that has a trigger, the trigger is activated only if the data is reloaded by using Import commands. The trigger is not activated when the data is reloaded by using Load commands because the Load utility cannot enforce the business rules that are associated with a trigger.

Important: If you choose a reload method that activates triggers, check the reload change commands file to verify the order that the data is reloaded. When the data is reloaded, the triggers might not be activated in the way that you intend.

From the Change Management Script Editor, you can click Data Options to start the Customize Data Preservation wizard, which helps you modify file locations, unload and reload methods, and unload and reload commands. Optim™ Database Administrator assumes that you have a shared file system between the source and target. If you do not, you must unload the data in one step, move the files, and then start the reload process. If the source and the target are on different systems and have a shared file system, you can use the Customize Data Preservation wizard to specify the data file path in the target.

To migrate data to a database that is on a remote server, the remote server must have access to the file location.

You cannot automatically back out migrated data because you cannot generate undo commands for data migration. However, if you deploy undo commands to roll back the changes that you have made to a database and a table is dropped and re-created as part of the undo, any data that you have copied over is effectively lost.


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