title: why use lookup transformation instead of just a source file with joiner?
body: <p>so i'm learning informatica powercenter</p>
  
  <p>(at least through cloud designer)</p>
  
  <p>i'm trying to figure out why we would use a lookup transformation to retrieve data based on a key, when we can just use a source transformation and join the data based on the key</p>
  
  <p>i did both situations and they both accomplished the same thing using 2 different tables (flat files, csv)</p>
  
  <p>why would i use a lookup transformation (besides having 1 transformation instead of 2 (source + joiner))</p>