I have not seen what you are wanting to do done before. I have a feeling it would really slow down the function of your database if it had to look and compare several fields. It would be much quicker to just have people enter the city and country.

What might help is to include instructions within your html_record_form so people will know for instance not to use abbreviations. Show an example of how you want the name of the school field filled in (to prevent dups with different spellings).

For instance above the field for the school name include something like this:
"Please do not use abbreviations for your school name, each school name should be spelled out in full (i.e. St. Peters would be entered as Saint Peters)"

I have found if you provide instructions and examples users are likely to follow your examples and help to keep things consistent within the database.

You can also use the following:

Make every word in a field Upper Case

$rec{'FieldName'} =~ s/(\w+)/\u\L$1/g; ## change words to start in upper case

Place this at the beginning of html_record form, and html_record or html_record_long.

This would prevent the problem with having people enter in all lowercase and having the entries being duplicated due to the case.

Hope this helps a little

Unoffical DBMan FAQ
http://webmagic.hypermart.net/dbman/