QUESTION NO: 28
Which two statements are true regarding working with dates? (Choose two.)
A. The default internal storage of dates is in the numeric format
B. The RR date format automatically calculates the century from the SYSDATE function but allows
the user to enter the century if required
C. The default internal storage of dates is in the character format
D. The RR date format automatically calculates the century from the SYSDATE function and does
not allow the user to enter the century
Answer: A,B
答案解析：
参考：80：http://blog.csdn.net/rlhua/article/details/12925323
Explanation:
Working with Dates
The Oracle Database stores dates in an internal numeric format, representing the century, year, month, day, hours, minutes, and seconds.
The default display and input format for any date is DD-MON-RR.
RR Date Format
The RR date format is similar to the YY element, but you can use it to specify different centuries.
Use the RR date format element instead of YY so that the century of the return value varies according to the specified two digit year and the last two digits of the current year. The table in the slide summarizes the behavior of the RR element.
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Note the values shown in the last two rows of the above table. As we approach the middle of the
century, then the RR behavior is probably not what you want.
This data is stored internally as follows:
CENTURY YEAR MONTH DAY HOUR MINUTE SECOND 19 87 06 17 17 10 43