PL / SQL编写更新列的过程？

Question

我应该根据程序将学生成绩更新为“ A”

ChangeGrade(p_sID, p_classID)

如果学生未注册该课程（p_classID），​​则会显示一条错误消息。

表格如下：

报名

sID    classID   Grade
***    *******   *****
104      10440     B
102      10220     C
...      .....     .

我应该进行内部联接吗？这是我所拥有的：

Create or Replace ChangeGrade (
  p_sID enrolling.sID%type
  p_classID enrolling.classID%type )
AS
  p_id_enrolled NUMBER;

BEGIN
  SELECT sID into p_id_enrolled 
  FROM Enrolling
  WHERE sID = p_sID
  AND classID = p_classID

  IF p_sID = p_id_enrolled THEN
    update Enrolling
    set GRADE = 'A'
    dbms_output.put_line('Student grade has been changed.')
  ELSE
    dbms_output.put_line('Student record does not exist.')
  END IF;
END;
/   

Answer 1

Create or Replace procedure ChangeGrade (
  p_sID enrolling.sID%type
  p_classID enrolling.classID%type )
AS
BEGIN
  update Enrolling
     set GRADE = 'A'
   where sID = p_sID
     AND classID = p_classID;
  IF SQL%ROWCOUNT > 0 THEN
    dbms_output.put_line('Student grade has been changed.');
  ELSE
    dbms_output.put_line('Student record does not exist.');
  END IF;
END;