现阶段长城商户通的主要功能包括哪些?
参考答案:
业主收款功能、业主付款功能、末笔交易明细查询打印、当日收款汇总查询、当日付款汇总查询、银行卡余额查询、短信实时提醒等。
A survey done recently shows that not all parents ________ their children taking part in the weekend classes.[ ]
A.escape from
B.lead to
C.accuse of
D.approve of
设关系R和关系S具有相同的属性个数,且相应的属性取自同一个域,则 t|t∈R∧┒t∈S t是元组变量 其结果关系是
A.R∪S
B.R-S
C.R∩S
D.R-(R-S)