The problem is that exchange rates changes every seconds and in this way the stored conversion will be old soon. That is why I need something done on the fly.

Maybe I could do it every time the user requests the page with converted amount to reduce total WU

I need only one currency convertion (EUR) so this is not a problem

About WU it would be more expensive to :

  • retrieve every time the repating group from a backgroudworkflow/api or
  • update conversion on DB every time the user (or background offline workflow) request the data and then retreive repeating group on page/workflow?
    (in SQL I would have solved with a joined view for example)

With both method I could solve my main issue that is to group and sum multicurrency payments. Is there any other way to do that?

Thank you!