在SQL SERVER 2008 中 BACKUP LOG WITH TRUNCATE_ONLY 已不再被支持，要收缩数据库日志，首先需要通过将数据库恢复模式设置为 SIMPLE 来截断该文件。语句如下：
USE DATABASENAME;
GO
-- Truncate the log by changing the database recovery model to SIMPLE.
ALTERDATABASE DATABASENAME SET RECOVERY SIMPLE;
GO-- Shrink the truncated log file to 1 MB.
DBCC SHRINKFILE (DATABASENAME_Log, 1);
GO-- Reset the database recovery model.
ALTERDATABASE DATABASENAME SET RECOVERY FULL;
GO
要收缩已做镜像的数据库的日志文档，用
USE DATABASENAME; GO
BACKUPLOG DATABASENAME TODISK='文件路径'
-- Shrink the truncated log file to 1 MB.DBCC SHRINKFILE (DATABASENAME_Log, 1); GO
BACKUPLOG DATABASENAME TODISK='文件路径'
-- Shrink the truncated log file to 1 MB.DBCC SHRINKFILE (DATABASENAME_Log, 1); GO