ORACLE PL/SQL 的异常处理

1) 基本结构
BEGIN
... --语句
EXCEPTION -- 异常处理
WHEN ...
...
WHEN OTHERS
...
END;

2)常用异常
EXCEPTION
WHEN CURSOR_ALREADY_OPEN THEN -- ORA-06511 SQLCODE = -6511 游标已经打开
...
WHEN DUP_VAL_ON_INDEX THEN -- ORA-00001 SQLCODE = -1 向唯一索引中插入重复数据
...
WHEN INVALID_CURSOR THEN -- ORA-01001 SQLCODE = -1001 非法游标操作
...
WHEN INVALID_NUMBER THEN -- ORA-01722 SQLCODE = -1722 字符向数字转换失败
...
WHEN LOGIN_DENIED THEN -- ORA-01017 SQLCODE = -1017
...
WHEN NO_DATA_FOUND THEN -- ORA-01403 SQLCODE = +100 没有找到数据
...
WHEN NOT_LOGGED_ON THEN -- ORA-01012 SQLCODE = -1012
...
WHEN PROGRAM_ERROR THEN -- ORA-06501 SQLCODE = -6501 程序错误
...
WHEN STORAGE_ERROR THEN -- ORA-06500 SQLCODE = -6500
...
WHEN TIMEOUT_ON_RESOURCE THEN -- ORA-00051 SQLCODE = -51
...
WHEN TOO_MANY_ROWS THEN -- ORA-01422 SQLCODE = -1422 返回多行
...
WHEN TRANSACTION_BACKED_OUT THEN -- ORA-00061 SQLCODE = -61
...
WHEN VALUE_ERROR THEN -- ORA-06502 SQLCODE = -6502 数值转换错误
...
WHEN ZERO_DIVIDE THEN -- ORA-01476 SQLCODE = -1476 被零除
...
WHEN OTHERS THEN -- 其它任何错误的处理
...
END;

declare
  v_a varchar2(10);
begin
  select count(*)/0 into v_a from v$session;
EXCEPTION
  when others then
    dbms_output.put_line(SQLERRM);
end;