So....let's have a look if I understood the issue:
-Find_all_by is actually the same like Find(:all), however Find_all_by
is much shorter and less complicated than the syntax of Find(:all)
-So in my CONTROLLER it says @files = find(:all) however I don't want
to see all files displayed in my selection box, because I only want to
see the foles whose mandant_id is the same like the mandant_id in
So i decided to change the @files = find(:all) into =>
Invoice is a class. What you're looking for is, I assume, the
mandant_id of a *particular* invoice. So you need to use the mandant_id
of that. Assuming you have grabbed that somewhere with another find
@my_invoice = Invoice.find(:first)
then your find_by will look like...
@files = File.find_all_by_mandant_id(@my_invoice.id)
Note that using 'File' as a model name is potentially problematic since
File is also a ruby class.