—先备份数据库(含日志文件） 
 use myhis 
 go 
 backup database myhis to disk=’d:\myhis_rzbak’ 
 go 
 —设为简单恢复模式 
 use [master] 
 go 
 alter database myhis set recovery simple with no_wait 
 go 
 alter database myhis set recovery simple 
 go 
 —收缩数据库日志文件为8M 
 use myhis 
 go 
 dbcc shrinkfile(myhis_log,8) 
 go 
 —重新设为完整恢复模式 
 use master 
 go 
 alter database myhis set recovery full with no_wait 
 go 
 alter database myhis set recovery full go