Data migration overview

Migrating data can be useful when you normalize tables and must 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.

To migrate data, you start the Migrate Data wizard from Migrate on the main menu. The wizard guides you through the process of selecting the table data to migrate and pairing the source tables that you want to unload the data from to the target tables that you want to load the data to.

When you migrate data, the data is always saved to external files. The data is unloaded to the external files with EXPORT commands and loaded into the target table with LOAD commands.

When you migrate data to a table that has a trigger, the trigger is not activated when the data is reloaded. The load utility cannot enforce the business rules that are associated with a trigger.

You can use the Review and Deploy wizard to specify the directory path for saving the data. The data is reloaded from this path. If the source and the target databases are not the same and are on different systems and have a shared file system, you must specify directory path for saving the data. The default location is most likely not on the shared file system.

To change how the unloaded columns are mapped to the columns that are being reloaded, you can click the Column Mapping button in the Review and Deploy wizard. A dialog opens where you can change the column mapping for unloaded and reloaded columns for each table.

You cannot automatically back out migrated data because you cannot generate undo commands for data migration.


Feedback