This DMU facility allows you to perform such tasks as upgrading DMS II software levels with no knowledge of DMS II.
Selecting this facility makes no other changes; it simply causes the required update processes to take place.
This facility is also useful when you wish to reorder a database data structure after adding a new Profile. This is because DMS II requires that a database update must have occurred before a newly added Profile can be used to reorder a data structure.
Note: As with all database changes, ensure you take a backup of your database and before performing a DMU Update.
To perform the update, the process requires exclusive use of the database control file. This means that the database, and therefore your application, must not be in use. If the database is in use the update process stops and you are asked if it is to continue.
If chosen, this option causes the specified database to undergo the following process, which is controlled by a WFL initiated by DMU:
The Database Source file (DASDL file) is recompiled, with the $UPDATE parameter set to update the Database Description file.
The DMSUPPORT Library and RECONSTRUCT program for the database are recompiled.
The Database control file is updated (DMCONTROL UPDATE).
If an error occurs during this process, all files are returned to their state as at the start of the process, and the process stops.
When to Use the DMU Database Update Facility
The DMU Database Update facility might be useful when:
No changes have taken place to your database, but you wish to upgrade your DMS II software level.
You want to use DMU to reorder an existing data structure by a newly added Profile.
You want to recreate your database management programs; for example, if you have a lost or corrupted DMSUPPORT program.
How to Perform a DMU Database Update
To perform a DMU database update, perform the following:
Back up your database and application, if possible. This includes your Audit files, existing database management software, and appropriate System files and programs.
Run the DMU program, from either the usercode of the target application or from a privileged usercode.
Enter the correct parameters for your database.
Enter Y in the UPDATE DMS LEVEL property only, and transmit.
Monitor the DMU WFL to ensure that the process completes successfully. You should also read the report produced by the WFL.
You might optionally choose to perform another full backup of your application and database after the DMU update completes.
DMU Database Updates and the Remote Database Facility
If a DMU database update is performed, and the database is a primary Remote Database Facility (RDB) database, then the DMU database update is automatically applied to the secondary database as well.
If the secondary database is not available, the DMU WFL process displays an error message indicating that the update to the secondary database has not occurred. An example of this might be where the network connection to the secondary host is inoperative. This will have no effect on the update to the primary database.
Refer to Backup, Recovery, and Remote Database Facility for more information on the Remote Database Facility.