CREATE PROCEDURE UPDATECOURSEINFO
      @courseid char(10),
      @coursename varchar(30),
      @hour int,
      @returnString varchar(100) out
AS
BEGIN TRAN
     IF NOT  EXISTS( SELECT CID FROM COURSES WHERE CID=@COURSEID)
         BEGIN
              SELECT @returnString='課程信息不存在'
              GOTO ONERROR
        END
    --新增課程信息
     UPDATE COURSES SET hour=@hour WHERE cid= @courseid and cname=@coursename   
     IF  @@ERROR<>0 
            BEGIN
                 SELECT @returnString='修改課程信息失敗'
                 GOTO ONERROR
            END 
 ---------錯誤處理
      SELECT @returnString='修改課程信息成功'
      COMMIT TRAN
ONERROR:
      ROLLBACK TRAN
GO