Unmounting a Database

When you unmount a database, you remove the database and its devices from an SAP ASE.

The unmount command shuts down the database. All tasks using the database are terminated. The database and its pages are not altered and remain on the operating system devices. This figure shows what happens when you unmount a database from a system.

Graphic showing a server connected to two devices. After the unmount occurs, the server is connected to only one device, and there is an entry in the manifest file describing the event.

Note: With unmount, you identify more than one database for a move operation. However, if a device is used for more than one database, all of the databases must be moved in one operation. You specify the set of databases being transported. The devices used by these databases cannot be shared with any extraneous database besides the ones specified in the command.

The unmount command limits the number of databases that can be moved in a single command to eight.

The unmount command:

Shuts down the database,
Drops the database from the SAP ASE,
Deactivates and drops devices,
Uses the manifest_ file clause to create the manifest file.

Once the unmount command completes, you can disconnect and move the devices at the source SAP ASE if necessary.

unmount database <dbname list> to <manifest_file> [with {override, [waitfor=<delay time]} ]

For example:

unmount database pubs2 to "/work2/Devices/Mpubs2_file"

If you now try to use the pubs2 database, you see:

Attempt to locate entry in sysdatabases for database 'pubs2' by name failed - no entry found under that name. Make sure that name is entered properly.

Note: When the referencing database is dropped by the unmount command with an override, you cannot drop the referential constraints (dependencies) or table.