title: Informatica SET Mapping variable
body: <p>I'm new to informatica. I defined a mapping variable in the 'parameters and variables' option in a mapping.</p>
  
  <p>Now in an expression, I need to update the value of the mapping variable depending on the value of the records and also refer to its value at the same time.</p>
  
  <p>Basically, why can't I set the value of a mapping variable in an expression in real time? When I do use SETVARIABLE($$VAR,value), the value gets reflected only after the session ends and not during the session..</p>