Question regarding upgrading packages from a new developer

[Eric Hudish]

I'm new to building rpm based packages and have some questions regarding
best practices and management of a repository. 

I built a base rpm. It installs correctly without issue. The uninstall
section removes a specific directory root, say something like
[/usr/share/myproject] where I put some general data for use.

Here's where I'm getting confused and can find little information when
googling:

* I then built an upgrade version which contained all the same
configuration files and upgraded programs. When running 'rpm -U' it
proceeds to delete the [/usr/share/myproject] directory because of the
uninstall executing AFTER the update.

Here's where I'm confused. 
First: I'm surprised the unistall is executed at all on an upgrade...but
I can imagine the reasons for it. I've seen the documentation so...I can
live with it I guess.
Second: I would think the originating package would be uninstalled
before the new package or update. Why would it be done after?

So how can I manage this properly? Can anyone provide further reading or
documentation on this topic?

Essentially I seem stuck in the 'how do I build a package that properly
upgrades something I wrote before'? There doesn't seem to be alot of
reading on build and manage rpm upgrades...so to speak...

Thanks in advance! 

--
Eric M. Hudish

"It's Bucket 'o Nothing! Surprise your friends, amaze your family, annoy
perfect strangers! "