it kind of sounds like the client has your application already in place, and when they upgrade, they need to run scripts too?

I know in our case, we've done it both ways: we made one application have the ability, besides the usual presentation app, to also have the ability to run scripts in a massive transaction, and then auto-upgrade itself (exe, dlls files).

for the clients that are more technically savvy, I created a Schemachecker app that lets them see if they are on the "right" version for the script they plan on running, and then we provide the scripts and .msi for an install/upgrade process as well.

probably the most frustrating thing for me as far as scripting DDL is circular references, where TableA references TableB, which eventually, indirectly or directly, references back to TableA again.