Migrating changes by using the Compare Editor

When the differences between two databases are difficult to determine, using the Compare Editor to find and move those differences makes it easier to migrate changes from one database environment to another. In addition to a database connection, the source of the changes can also be a physical data model or a DDL script file.

Before you begin

A connection must exist to the database to which you want to migrate changes. If the source of the changes is a database, a connection must exist to that database.

Procedure

To migrate changes from a source (database connection, physical model, or DDL file) to another database by using the Compare Editor, complete the following steps:

  1. Create a change management script. In the Administration Explorer, right-click the Change Management Scripts folder for the database that you want to migrate changes to and click New Database Change. A new change management script is created, and the change management script is displayed in the Change Management Script Editor..

    A data design project is automatically created in the Data Project Explorer. The name of the data design project is the name of the database connection. If a data design project with the name of the database connection exists, the name of the new data design project is the database connection name with a numeric suffix. The data design project contains and manages the resources that are necessary to implement the changes to the actual database.

    Tip: To reuse an existing change management script, complete the following steps to reset the script:
    1. If the change management script is already open, click the tab for the script to ensure that the script is highlighted. Otherwise, in the Administration Explorer, expand the Change Management Scripts folder. Double-click the change management script that you want to open.
    2. From the main menu, click Change Management > Reset.
  2. From the main menu, click Change Management > Compare and Migrate Objects. The Migrate Objects to Target Model wizard starts.
  3. Complete the steps in the wizard, and click Finish.
    You can do these actions in the wizard:
    • Specify the source from which to migrate the changes.
    • Specify the objects that you want to migrate. For example, you can choose to migrate buffer pools, partition groups, schemas, table spaces, users, and groups.
    • Define masks and ignores to simplify what is included in the comparison.
    • Use Next Difference (
      icon image of down arrow for Next Difference button
      )and Previous Difference (
      icon image of up arrow for Previous Difference button
      buttons in the toolbar in the structural comparison table to drill down through the objects to identify the differences between models of the source and target database. Use the Copy from Left to Right (
      icon image of Copy from Left to Right button
      ) button in the toolbar to copy a difference that you want to apply to the target database.

    After you click Finish, the Change Management Script Editor shows the list of objects that were migrated to the database and the changes that will be made to the database.

  4. In the Change Management Script Editor, assess any other objects that might be impacted by migrating the changes to the target database.
    1. In the Objects to be Changed list, click each object. Objects that are affected by the objects that are being migrated are displayed in the Impacted Objects list.
    2. Include impacted objects in the change management script. Use the Alter and Drop buttons to move the impacted objects to the Objects to be Changed list. If you use the Alter button to move an impacted object, you can click the object and make any necessary changes to the object in the Properties view.
  5. Click Preview Commands to display the generated commands in the Commands section and review the commands.

    To review a summary of the changes that will be made to the database, click View Change Report.

  6. Click Data Options to start the Customize Data Preservation wizard and complete the steps in the wizard. You might want to customize commands when changes to a table require that the table be dropped and then re-created for any of the following reasons:
    • To modify the location of the data files
    • To change the load and reload methods
    • To redefine the query for unloading the data
    • To correct mismatches between the data types of unload and reload columns
    • To remap how the data is loaded

    You can also specify which DB2 maintenance commands are generated.

  7. Review the regenerated commands.
  8. Click Run to start the Deploy Change Commands wizard.
  9. Review the change commands and click Finish to deploy the changes to the actual database catalog.

Results

You have migrated structural database changes from one database environment to another. When you use the Compare Editor to migrate changes, you can migrate only structural database changes. To migrate data from other objects, you must complete additional steps.

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