title: Rails 4. Migrating (some) legacy DB data from old db to rails existing DataBase
body: <p>I have a task to import old data from old DB to new Rails app. Old program was created in Delphi and is outdated so customer decided create rails app for replacing it. I have dump file, and I am creating local MySQL db now and inserting there data for last 8 years (mysql is working for over an hour already) :)</p>
  
  <p>Now I am not sure about the way old data should be imported. The problem is that old db tables and columns are named differently from what I have in my App and there are many of unused and unneeded columns/tables there. So I need select only some of them and insert into App DB. Could You please suggest the best solution for this case?</p>
  
  <p>Thank you in advance!</p>