运行结果如下：
原字符串：1788987565327、768374872394903、21437238740213483874629、23412341234252345
14:03:38 **** SCRIPT STARTED: 02-Apr-2015 14:03:38 ****
14:03:38 declare
14:03:38 targetstr varchar2(2000);
14:03:38 ...
14:03:39 PL/SQL block executed
1788987565328、768374872394904、21437238740213483874620、23412341234252346
14:03:39 **** SCRIPT ENDED 02-Apr-2015 14:03:39 ****
14:03:39 End Script Execution