begin
    if v_ch is null or v_from is null then
        return 'error';
    end if;
   
     if instr(v_ch,':') = 0 or instr(v_from,':')= 0 then
         return 'error';
     end if;
   
    temp_v := v_ch;
     loop
         fenhao_address := instr(temp_v,';');
         if fenhao_address=0 then
              --没有找到分号,则为最后一组属性名：属性值
              v_pv := temp_v;
              --检查属性是否是要替换的属性
              if v_pv != v_from then
                     result_v := result_v||';'||v_pv ;
              else
                    if v_to is not null then
                       result_v := result_v||';'||v_to;
                    end if;
              end if;
              --跳出循环
              exit;
          else
             --取出属性对
             v_pv := substr(temp_v,1,instr(temp_v,';')-1);
              --检查属性是否是要替换的属性
              if v_pv != v_from then
                  result_v := result_v||';'||v_pv ;
              else
                 if v_to is not null then
                       result_v := result_v||';'||v_to;
                 end if;
              end if;
             --得到剩余的属性对
             temp_v := substr(temp_v,instr(temp_v,';')+1);
          end if;        
     end loop;
    
     --对结果进行处理,去掉最左侧的分号
     if substr(result_v,1,1)=';' then
          result_v := substr(result_v,2);
     end if;
     --返回结果
     return result_v;
end sp_replace_property_value;