jbe/bsw@0: --[[--
jbe/bsw@0: param.update(
jbe/bsw@0:   record,               -- database record to be updated
jbe/bsw@0:   key_and_field_name1,  -- name of CGI parameter and record field
jbe/bsw@0:   key_and_field_name2,  -- another name of a CGI parameter and record field
jbe/bsw@0:   {
jbe/bsw@0:     key3,               -- name of CGI parameter
jbe/bsw@0:     field_name3         -- name of record field
jbe/bsw@0:   }
jbe/bsw@0: )
jbe/bsw@0: 
jbe/bsw@0: This function can update several fields of a database record using GET/POST request parameters (or internal/exchanged parameters). The type of each parameter is automatically determined by the class of the record (_class:get_colums()[field].type).
jbe/bsw@0: --]]--
jbe/bsw@0: 
jbe/bsw@0: function param.update(record, mapping_info, ...)
jbe/bsw@0:   if not mapping_info then
jbe/bsw@0:     return
jbe/bsw@0:   end
jbe/bsw@0:   assert(record, "No record given for param.update(...).")
jbe/bsw@0:   assert(record._class, "Record passed to param.update(...) has no _class attribute.")
jbe/bsw@0:   local key, field_name
jbe/bsw@0:   if type(mapping_info) == "string" then
jbe/bsw@0:     key        = mapping_info
jbe/bsw@0:     field_name = mapping_info
jbe/bsw@0:   else
jbe/bsw@0:     key        = mapping_info[1]
jbe/bsw@0:     field_name = mapping_info[2]
jbe/bsw@0:   end
jbe/bsw@0:   assert(key, "No key given in parameter of param.update(...).")
jbe/bsw@0:   assert(field_name, "No field name given in parameter of param.update(...).")
jbe/bsw@0:   local column_info = record._class:get_columns()[field_name]
jbe/bsw@0:   if not column_info then
jbe/bsw@0:     error('Type of column "' .. field_name .. '" is unknown.')
jbe/bsw@0:   end
jbe/bsw@0:   local new_value = param.get(key, column_info.type)
jbe/bsw@0:   if new_value ~= record[field_name] then
jbe/bsw@0:     record[field_name] = new_value
jbe/bsw@0:   end
jbe/bsw@0:   return param.update(record, ...)  -- recursivly process following arguments
jbe/bsw@0: end