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.
from the same book as mentioned earlier. (i.e. this is not my opinion)
D. Flashback Versions Query does not change data at all, so option A is incorrect. B could be correct, but only if one of the specified points in time was the current timestamp. Therefore, B is not the best description. Option C is incorrect because Flashback Versions Query does not provide the SQL to undo the changes.
This is my opinion…
Is the term “current timestamp” so significant and different from “the time the query was executed”?
“a point in time in the past” is even more ambiguous so I don’t agree with the answer given here.
I think the correct answer should be B.
Anyway this question will not appear on the exam, so relax….
Please ignore the “source” I have given for the question and answer above, as I cannot determine exactly where I got it.
D is correct:
https://docs.oracle.com/cd/E11882_01/appdev.112/e41502/adfns_flashback.htm#ADFNS01004
Specify Oracle Flashback Version Query using the VERSIONS BETWEEN clause of the SELECT statement. The syntax is:
VERSIONS {BETWEEN {SCN | TIMESTAMP} start AND end}
Oracle Flashback Version Query returns a table with a row for each version of the row that existed at any time during the specified time interval. Each row in the table includes pseudocolumns of metadata about the row version, described in Table 12-1. This information can reveal when and how a particular change (perhaps erroneous) occurred to your database.