单项选择题 Whichbackgroundprocessreadstheredologbufferandwritesittoafile？（）

单项选择题 You have performed the first step in placing your database into ARCHIVELOG mode. The second step is deciding whether the online redo log files are to be archived automatically or manually.  Which action should you take to enable archiving at instance startup？（）

单项选择题 When performing an incomplete recovery of the whole database， what must be true about the data files that are restored？（）