当关系引用了属性名以后，关系具有的性质中不包括______。

A) 事务处理
B) 使用游标
C) 合理使用索引
D) 不充分的连接条件

A) SELECT Sname
FROM S，SC，C

WHERE S.Sno=SC.Sno AND SC.Cno=C.Cno AND Teacher=‘LIU’AND Ssex=‘F’
B) SELECT Sname

FROM S WHERE Ssex=‘F’AND Sno IN



(SELECT Sno



FROM SC



WHERE Cno IN(SELECT Cno FROM C




WHERE Teacher=‘LIU’))
C) SELECT Sname

FROM S WHERE Ssex=‘F’AND EXISTS (SELECT*





FROM SC





WHERE SC.Sno=S.Sno AND EXISTS





(SELECT*





FROM C





WHERE Teacher=‘LIU’))
D) SELECT Sname
FROM S WHERE Ssex=‘F’AND EXISTS(SELECT*





FROM SC





WHERE SC.Sno=S.Sno AND EXISTS





(SELECT*





FROM C





WHERE C.Cno=SC.Cno AND Teacher=‘LIU’))