I find that during the course of building a Drupal site, oftentimes I find myself wishing that I had created more descriptive field names. As in, why was this field named field_blah when field_foo makes the purpose so, so much clearer. It's something of a cosmetic issue, to be sure, but also one that has to do with basic professionalism and organization - trying to make a site as clean and optimal as possible.
There are a variety of approaches to doing this. There is even a Drupal module: http://drupal.org/project/cck_field_rename ... which I tried out and it broke the database. Oh, well, that's why one should always make a backup before doing ANYTHING with one's data.
So, what do I think is the best way to do it? Well, just create a new CCK field with the name you want, move the data over with a MySQL query.
If the columns are in the same table (i.e. you're just changing the name and not the field type) it's as easy as:
UPDATE yourTable SET newColumnName = oldColumnName
If they aren't it would be more like this:
UPDATE newTable LEFT JOIN oldTable ON newTable.nid = oldTable.nid SET newTable.newTableColumn = oldTable.oldTableColumn
Voilà, painless... takes about 30 seconds including all the logins.
