Summary: Controlling "ad hoc" queries

In article <lapscgINN8jg_at_news.bbn.com> Nat Brooks, NBROOKS_at_BBN.COM writes:
>Has anyone out there successfully installed and supported an end user
>query tool that was actually used by end users? How did you prevent
>"monster" queries? How did you handle users formulating queries that
>returned misleading results? How did you /will you handle changes in the
>database schema?

That's what I asked a few days ago. The summary is that there is no summary. I did get asked to post a summary of responses, so here it is. Noone has replied with stories of success.

Now that I've taken care of that piece of business, I'll open the question up a little:

Are "user query tools" a dead end, due to inadequate protection against "incorrect" queries?
If so, what are the alternatives (rapid development of query applications, improved report
writing tools...)?. If not, how are they best used (only with heavy training for users, small databases only, on extracted "reporting" databases...)?

My intention here is to stimulate discussion. Speculate away!

• Nat Brooks