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.
查看答案
机械开挖沟槽应预留一定厚度土层,由人工开挖至槽底设计高程,其厚度为()。
A. 50~100mm
B. 100~150mm
C. 150~200mm
D. 200~300mm
《中华人民共和国反洗钱法》的施行日期是()
A. 2007-1-1
B. 2007-3-1
C. 2007-7-1
D. 2007-10-1