【判断题】若属性A是基本关系R的主属性,A可以取空值
【单选题】¿ cuál es la que no tiene nada que ver con la religión?
【单选题】It was _____ she was injured in the accident _____ she didn't come to the party yesterday. [ ]
【多选题】根据参照完整性规则,若属性组F是基本关系R的外码,F与基本关系S的主码相对应,则F在R中的取值可以是( )。
【单选题】It was __________she was injured in the accident _______ she didn’t come to the party yesterday.
B.
because; that C since; why D. for; how
【单选题】对全市工业企业职工的生活情况进行调查,调查对象是( )。
【简答题】(reveal, novelty, dispute, immune, inspire, extract, substance, incite, reconcile, consult) 2. 这种青霉素非常罕见,能够产生大量抗菌物质。 It was a rare type extraordinarily productive in antibacterial ________.
【判断题】La religión es un conjunto de creencias y dogmas.