I have some input steps that I am going to use in several transformations in a DWH ETL.
Some of them read data from files and other from database tables.
I would like to reuse this transformations....¿what is the best choice?, ¿use a subtransformation?, ¿can I use a subtranformation without a input mapping?, I mean only ouput mapping....

I want to create some resuable steps or transformations that when the structure of the input file or the database table change I only have to change this step or transformation

Any help will be greatly appreciated.