Many changes to the database structure — including adding and removing columns or tables and modifying stored procedures — can be made while the database is running. You do this by updating the application catalog.
Once you rebuild the catalog, the Enterprise Manager not only helps you do the update, it lets you compare the two catalogs (the current and the new catalog) to see what changes they contain before finalizing the change. The following sections explain how to update the catalog using the Enterprise Manager dashboard.
Click on Edit in the catalog settings panel to bring up the Edit Catalog dialog box.
When you first bring up the dialog box, it shows you information about the current catalog. To update to a new catalog, click on the Browse... button, select a new catalog from your system, and then click OK.
Once the Enterprise manager loads the new catalog, the Edit Catalog dialog changes to show you the changes between the current catalog and the new catalog. In particular, the dialog shows you any differences (whether additions, deletions, or modifications) in the schema tables or stored procedures.
Once you compare the changes between the new catalog and the current catalog and are satisfied that they are changes you want to make, click the OK button one more time to commit the update.
If the database is running and the changes in the catalog are consistent with updating the database "on the fly", the Enterprise Manager will update the catalog information on the dashboard and update the database as well. If the catalog contains changes that require a restart, you will receive a warning that the catalog cannot be updated while the database is running. In this case, you will need to cancel the update, stop the database (taking the appropriate snapshot if you wish to save the data beforehand), then update the catalog, and restart the database.
If the database is stopped, any catalog changes are possible. The catalog is updated as soon as you click OK.