Help your customer get what they really want (Score 1)

I think your customer has a legitimate need, which is to be able to get answers out of data that you store and manage for them. Although your customer thinks direct access is the best solution to get these answers, it may not really help them because non-DBA users often don't understand the database structure or the SQL syntax that's necessary to make use of the data.

I'm with Kirix, and we currently have a similar situation with one of our clients: they have a backend database that they don't want their users to access, but their end-users want the ability to do ad-hoc analysis on the data.

Our solution was to set up a nightly job to extract out relevant portions of the data into CSV files and post them to a secure website. The users can then open the CSVs directly by clicking on their hyperlinks in Kirix Strata, and then manipulate them directly any way they want with a simple interface. As a result, 1) the users get what they really need, which is the ability to do ad-hoc reporting on the data, 2) the database remains secure, and 3) the solution is easy to extend by making additional data available via new hyperlinks on the secure website.

In your case, this may work well, as long as the individual data tables you post are reasonably sized (less than 1 million records).