明天就考试了,向大家请教几道题~~
1. The HAVING clause works just like the WHERE clause, except that( )
A. It operates after aggregate functions have been calculated.
B. It operates before aggregate functions have been calculated.
C. It has not impact on the aggregate functions calculated.
D. None of the above.
答案给的是A,我就搞不懂,这两个字句和聚合函数有什么关系?
2. Which is not the benefits of placing a Transuction Log on a separate device from the database device? ( )
A. Increase performance for logged operations because the I/O requests for a database are divided between two devices.
B. Backups are faster and more convenient because the log can be backed up separately from the database.
C. If frequent modifications are made to the log, it will compete for space with database.
D. Using Performance Monitor allows you to monitor the exact amount of log space used.
答案是C,D中的Performance Monitor 是什么东西,为什么数据文件和日志文件不放在一起就可以准确的得到日志文件的大小?
3. What happens to your SQL Server if the transaction log runs out of space?
A. The log starts over, overwriting the first transactions from the oldest to the newest.
B. The log dumps to the transaction log dump device and then resets.
C. You are unable to continue any standard operations until either the transaction log or database has been dumped.
D. The SQL Executive raise an alert.
答案是C,可我觉得是A。
4. What statement is true in regards to inserting a DEFAULT value to a column?
A. The column must have a default value if it prohibits nulls.
B. The column must not be a NO NULL.
C. The column must be NULL.
D. The column must be empty.
答案是A,可我觉得都不对,如果A把must改称had better还差不多。
5. An aggregate function cannot be combined in a Select list with simple column names.
这句话是什么意思,Select list是什么东西?
请大家帮我瞅瞅,答案不一定是对的!!!
谢谢大家~~