【单选题】某程序将计算结果输出到一个有格式顺序文件中,文件名为AA.DAT,设备通道号为3。打开这个文件的是下列中的哪条语句? A.OPEN(UNIT=3,FILE=AA.DAT,STATUS—NEW)
B.
OPEN(UNIT=3,FILE—AA.DAT,STATUS=OLD)
C.
0PEN(3,FILE=‘AA.DAT’,STATUS=‘NEW’)
D.
OPEN(3,FICE:‘AA.DAT’,STATUS=‘OLD’)提示:因为是写文件,STATUS的值应为NEW,并要加引号。
【单选题】When his father started questioning his explanation, he had to ____ more details for his mistakes.
【判断题】When Michael started to record music on his own, the group didn’t perform together anymore.
【判断题】数据库系统总会产生很多临时文件的原因是:顺序文件不能像顺序表那样进行插入、删除和修改,只能通过复制整个文件的方法实现上述更新。