Important notes:

  -At measures table, 'PIECES' MUST BE id=1 at whichever translated string is. That is because a hardcoded way of implementing the method to
   know if a product is sold by pieces or other measure, to decide if at inserting a product we must ask the user to enter the amount to
   be sold, for example how many kilograms of sugar; and not asking when selling a chocolate bar that is sold by piece. 
   
  -At Clients table, the default client ID IS 1, at whichever translated string is. This is the one that is to be selected by default.
