4、　　编写一个过程。要求：有一个输入参数和一个输出参数，过程里面要有自定义异常。从学生表中（tab_student）中寻找符合指定学号等于输入参数的值，然后将找到的学生的姓名赋予输出参数，如果没有符合条件的值则触发异常。

Create table tab_student

(sno char(8),

sname varchar2(20),

age integer,

province varchar2(60),

sex char(4))

insert into tab_student values(‘001’,’zhou’,20,’江苏徐州’,’男’)

上述表已经创建，只需针对此表编写即可。

-4, the preparation of a process. Requirements: have an input parameter and an output parameter, the process which must be custom exception. From the student table (tab_student) to find places to comply with the specified number of values equal to the input parameters, and then will find the names of the students entrusted to output parameters, if there is no eligible trigger abnormal value. Create table tab_student (sno char (8), sname varchar2 (20), age integer, province varchar2 (60), sex char (4)) insert into tab_student values (