Hi Doug and welcome to the forums!
You really should avoid messing with the vCenter database directly. Running SQL statements against it should only be done when advised by VMware support or at least by a KB article.
In the VMware KB you will find a lot of articles about cleaning up the vCenter database. This one might be a good start:
http://kb.vmware.com/kb/1007453
Andreas
Twitter: @VFrontDe, @ESXiPatches | https://esxi-patches.v-front.de | https://vibsdepot.v-front.de