How to perform a data transformation on a data table?

Say I want to create a duplicate of field which already exists in the data table although would like to perform a data transformation, it would be nice to be able to do so on say the following page: admin/build/data/edit/tablename

Perhaps we could use code like a regular expression or another module such as "feeds tamper"

http://drupal.org/project/feeds_tamper

Examples from feeds tamper:

Replace every instance of 'dog' with 'cat'.
Filter items based on keywords or vocabularies.
Make every letter uppercase, lowercase, or capitalize every first letter.
Break a comma separated list of words into Taxonomy terms or a multivalued text field.
Combine separate 'firstname' and 'lastname' fields into one 'name' field.
Convert urls from relative to absolute.