我有完全备份，差异备份，和日志备份三种备份
代码分别是：
完全： backup database mydb to disk=’E:\Backup\mydb.bak’
差异：backup database mydb to disk=’E:\Backup\mydb.bak' WITH DIFFERENTIAL,INIT
日志：backup log mydb_log to disk=’E:\backup\mydb.trn’请问与之对应的三种恢复语句分别怎么写？
另外完全备份时我想把在这之前的数据库日志删掉(不是删备份)，要是不删日志就会越来越长，请问怎么截断日志？
代码分别是：
完全： backup database mydb to disk=’E:\Backup\mydb.bak’
差异：backup database mydb to disk=’E:\Backup\mydb.bak' WITH DIFFERENTIAL,INIT
日志：backup log mydb_log to disk=’E:\backup\mydb.trn’请问与之对应的三种恢复语句分别怎么写？
另外完全备份时我想把在这之前的数据库日志删掉(不是删备份)，要是不删日志就会越来越长，请问怎么截断日志？
RESTORE DATABASE [mydb ] FROM DISK = N'E:\Backup\mydb.bak' WITH FILE = 1, NORECOVERY, NOUNLOAD, STATS = 10
GO
RESTORE DATABASE [mydb ] FROM DISK = N'E:\Backup\mydb.bak' WITH FILE = 2, NORECOVERY, NOUNLOAD, STATS = 10
GO
RESTORE LOG [mydb ] FROM DISK = N'E:\Backup\mydb.trn' WITH FILE = 3, NOUNLOAD, STATS = 10
GO
SQL还原
======================================================================
1、验证备份
------------------------------------------------------------
restore headeronly from bak3
restore filelistonly from bak3 with file=1
restore labelonly from bak3
restore verifyonly from bak3
----------------------------------------------------------------------
2、从备份中还原
-------------------------------------------------------------------------
restore headeronly from bak1
restore database d1 from bak1 with file=2 --从完全备份中恢复
----------------------------------------------------------------------
restore headeronly from bak2 --从差异备份中恢复
restore database d2 from bak2 with file=1,norecovery
restore database d2 from bak2 with file=5,recovery
----------------------------------------------------------------------
restore headeronly from bak3 --从日志备份中恢复
restore database d3 from bak3 with file=1,norecovery
restore log d3 from bak3 with file=2,norecovery
restore log d3 from bak3 with file=3,norecovery
restore log d3 from bak3 with file=4,norecovery
restore log d3 from bak3 with file=5,recovery
----------------------------------------------------------------------
restore database d3 from bak3 with file=1,norecovery --恢复到指定时间
restore log d3 from bak3 with file=2,norecovery
restore log d3 from bak3 with file=3,norecovery
restore log d3 from bak3 with file=4,recovery,stopat='2003-08-15 11:29:00.000'
----------------------------------------------------------------------
restore database d5 filegroup='FG2' from bak5 with file=4,norecovery --还原文件组备份
restore log d5 from bak5 with file=5,norecovery
restore log d5 from bak5 with file=7,recovery
----------------------------------------------------------------------
restore headeronly from bak6 --还原文件备份
restore database d5 file='d5_data3' from bak6 with file=6,norecovery
restore log d5 from bak6 with file=7,norecovery
restore log d5 from bak6 with file=9,recovery
----------------------------------------------------------------------
restore database d5 from bak6 with replace --删除现有数据库，从备份中重建数据库
----------------------------------------------------------------------
create database d6 --move to将数据库文件移动到新位置
on primary
(name=d6_data,
filename='E:\Program Files\Microsoft SQL Server\MSSQL\data\d6_Data.MDF',
size=2MB)
log on
(name=d6_log,
filename='E:\Program Files\Microsoft SQL Server\MSSQL\data\d6_log.ldf',
size=2MB)
go
backupdatabase d6 to bak6 with init
drop database d6
restore database d6 from bak6
with move 'd6_data' to 'e:\data\d6\d6_data.mdf',
move 'd6_log'to 'e:\data\d6\d6_log.ldf'
sp_helpdb d6
----------------------------------------------------------------------
3、分离与重连接数据库
--------------------------------------
sp_detach_db 'd6'
sp_attach_db 'd6','e:\data\d6\d6_data.mdf','e:\data\d6\d6_log.ldf'
--------------------------------------
sp_detach_db d6
go
create database d6
on primary
(filename='e:\data\d6\d6_data.mdf')
for attach
go
----------------------------------------------------------------------
4、恢复损坏的系统数据库
----------------------------------------------------------------------
1）先备份MASTER、MSDB
2）停止SQL服务，将MASTER数据库文件删除或者重命名。这样，SQL服务将不能启动。
3）系统数据库的还原
-----------------------------------------------
（1）如果SQL服务还能启动，则从备份中恢复系统数据库。
（2）如果SQL服务不能启动，则需要重建系统数据库。
使用SQL文件夹TOOLS\BINN目录下的Rebuildm.exe重建master数据库。
（3）创建备份设备，指向以前的备份设备。
（4）以单用户模式启动SQL
cd programe files\microsoft sql server\mssql\binn
sqlservr.exe -c -m
（5）进查询分析器，从备份中恢复master数据库。
restore database master from masterbak
restore database msdb from disk='e:\bak\msdb.bak'
MASTER还原后，SQL中用户数据库的信息也会恢复。
（6）如果MASTER没有备份，则需要用sp_attach_db命令将用户数据库附加到新的MASTER数据库中。