Because a database snapshot provides a static view of a database , a snapshot can extend access to data from a particular point in time 由于数据库快照可提供数据库的静态视图，因而可以通过快照访问特定时间点的数据。
A configuration of servers that includes one primary server , one or more secondary servers each with a secondary database , and a monitor server 恢复路径( recovery path )使数据库到达特定时间点（称为恢复点）的一组数据和日志备份。
Under the full recovery model , you can specify the recovery point as a particular point in time , a marked transaction , or a log sequence number 在完整恢复模式或大容量日志恢复模式下，可以将恢复点指定为特定时间点、标记的事务或日志序列号。
Contains information about how to recover to a point in time by recovering only the transactions that occurred before a specific point in time within a transaction log backup , instead of the whole backup 包含有关如何通过只恢复在事务日志备份内特定时间点之前发生的事务（而不是整个备份）来恢复到某个时间点的信息。
With recovery includes both the redo and undo phases and recovers the database ; additional backups cannot be restored . this is the default . if the roll forward set has not been rolled forward far enough to be consistent with the database , the undo phase cannot occur 每个恢复路径都包含一系列将数据库恢复到特定时间点的数据和日志备份，该特定时间点可以是当前时间（通过正常使用数据库和备份） ，也可以是特定数据和日志还原。
