Lesson 7	Archive log backup set
Objective	Identify archive log backup sets.

Archive log Backup Sets

Archive logs are the log files that have been filled by your Oracle8 database. You can back up your archive logs whether the database is open or closed.
You can have numerous archive logs. The following table lists syntax options for specifying which archive logs to include in a backup set.

`ARCHIVELOG ALL`	This will copy all currently archived logs to the backup set.
`ARCHIVELOG LIKE 'string'`	The value of the string literal is used for the selection of archive logs. You would usually use this form of`ARCHIVELOG` syntax with a wildcard and a standard naming convention.
`ARCHIVELOG FROM/UNTIL 'time'`	These two syntax options allow you to specify a start time and an end time for the date on the archive log. If you use only the`FROM` option, the backup set will include the archive logs from the specified time until the current time. If you use onlythe `UNTIL` option, the backup set will include the archive logs from the earliest log until the specified time.
`ARCHIVELOG FROM/UNTIL scn`	These two syntax options work the same as the time options above, except that the scn variable is an integer that represents asystem control number.

Parallelism and Data Files

Potentially, you could have quite a few archive log files in your backup set, and you may not even know how many files will be in the set when you start the job. For this scenario, the number of channels you allocate and the filesperset option can have a much more varied impact.
The following SlideShow illustrates this scenario:

Parallel Archive log Backup

Parallelism Backup Sets - Quiz

Click the Quiz link below to test your knowledge of parallelism and the creation of backup sets.
Parallelism Backup Sets - Quiz
The next lesson is the module wrap-up.