public String getColumnData(int i) throws Exception {
	   if (i == 0)
		   return getPersonID();
	   else if (i == 1)
		   return getName();
	   else if (i == 2) 
		   return getProjectID();
	   else if (i == 3)
		   return getRole();
	   else
		   throw new Exception("Error: invalid column index in courselist table");    
   }