I have a prerequisite that installs a particular instance of SQL Server 2005 Express. Should the main installation fail for any reason, I want to rollback the prerequisite installation. If left alone, the instance could consume (wastefully) valuable resources on the installation machine.
Here are my requirements:
-Install an SQL Server named instance. -Run a few SQL scripts. -If rollback, then remove the named instance. -If uninstall, then remove the named instance.
Problem: Near as I can tell, the only way to install the named instance is by launching Microsoft's setup, which is an MSI based installer. This prevents me from installing during the main installation's execute sequence.
Problem: The UI sequence doesn't experience rollback events, so the prerequisite, which can be installed from the UI sequence, cannot be removed during a rollback.
Since the UI sequence doesn't experience rollback events, I decided to add a custom action to the execute sequence which merely disables the service, rather than removing it.
Disabling the service, rather than removing the instance, is important for two key reasons: Reinstalling the instance at a later time will not automatically re-attach all the databases that were previously created. Nor does removing the instance delete any of its data files.
