【简答题】与地图要素位量有关的错误,我们称为( ),如缺失线条或缺失多边形。
【判断题】ABC分类法并不局限于分成三类,可以增加。但经验表明,最多不要超过五类,过多的种类反而会增加控制成本。
【单选题】Which of the following statements best describes Flashback Versions Query?()
A.
Flashback Versions Query is used to make changes to multiple versions of data that existed between two points in time.
B.
Flashback Versions Query is used to view all version changes on rows that existed between the time the query was executed and a point in time in the past.
C.
Flashback Versions Query is used to view version changes and the SQL to undo those changes on rows that existed between two points in time.
D.
Flashback Versions Query is used to view all version changes on rows that existed between two points in time.
【单选题】Which of the following statements is true regarding the VERSIONS BETWEEN clause?()
A.
The VERSIONS BETWEEN clause may be used in DML statements.
B.
The VERSIONS BETWEEN clause may be used in DDL statements.
C.
The VERSIONS BETWEEN clause may not be used to query past DDL changes to tables.
D.
The VERSIONS BETWEEN clause may not be used to query past DML statements to tables.
【简答题】A.groups B.sets C.species D.versions
【判断题】为了防止软件非法拷贝,可以在自己编制的软件中插入病毒程序,一旦有人非法拷贝了软件,就让病毒发作。
【单选题】“这个软件有两种版本”地道的英文翻译是( )
A.
This software has two versions.
B.
Two versions of the software are available.
C.
This softwares have two versions.