昨天我只是将数据库附加到SQL2012，然后各个数据库都做了收缩事务日志的操作
兼容级别这些都没有改
再附加回SQL2005的时候就报错
在SQL2012里附加，确实是90级别，但是在SQL2005死活附加不上
备份数据库再还原也是一样
重建事务日志也是一样
然后我做了一个实验，检查一下附加到SQL2012的数据库和附加到SQL2005的数据库，两个数据库的文件头有什么不同
注意：两个数据库的兼容级别都是90，附加到SQL2012之后我也没有动过兼容级别！！
我们用同一个数据库，分别附加到SQL2005上和SQL2012上，看一下附加之后数据库的文件头有没有改变
这个数据库的兼容级别是90的
附加到SQL2012之后，我也不改变他的兼容级别
查看文件头的SQL语句如下，实际上就是数据库的第0页：
DBCC TRACEON(3604,-1)
DBCC PAGE(dlgpos,1,0,3)
在SQL2012里和SQL2005里都执行一下
将结果复制粘贴到一个新建的记事本里，命名好
DBCC 执行完毕。如果 DBCC 输出了错误信息，请与系统管理员联系。
PAGE: (1:0)
BUFFER:
BUF @0x035D7380
bpage = 0x05BC0000 bhash = 0x00000000 bpageno = (1:0)
bdbid = 5 breferences = 0 bUse1 = 8142
bstat = 0xc00009 blog = 0x59ca2159 bnext = 0x00000000
PAGE HEADER:
Page @0x05BC0000
m_pageId = (1:0) m_headerVersion = 1 m_type = 15
m_typeFlagBits = 0x0 m_level = 0 m_flagBits = 0x208
m_objId (AllocUnitId.idObj) = 99 m_indexId (AllocUnitId.idInd) = 0 Metadata: AllocUnitId = 6488064
Metadata: PartitionId = 0 Metadata: IndexId = 0 Metadata: ObjectId = 99
m_prevPage = (0:0) m_nextPage = (0:0) pminlen = 0
m_slotCnt = 1 m_freeCnt = 7636 m_freeData = 2844
m_reservedCnt = 0 m_lsn = (132:328:1) m_xactReserved = 0
m_xdesId = (0:0) m_ghostRecCnt = 0 m_tornBits = 1431739479
Allocation Status
GAM (1:2) = ALLOCATED SGAM (1:3) = NOT ALLOCATED PFS (1:1) = 0x44 ALLOCATED 100_PCT_FULL
DIFF (1:6) = CHANGED ML (1:7) = NOT MIN_LOGGED
File Header Data:
Record Type = PRIMARY_RECORD Record Attributes = NULL_BITMAP VARIABLE_COLUMNS
Memory Dump @0x5D95C952
00000000: 30000800 00000000 2d000000 00000000 ?0…….-…….
00000010: 2c007a00 7a007c00 7e008200 86008a00 ?,.z.z.|.~…….
00000020: 8e009800 a200ac00 ac00b000 b400b800 ?…………….
00000030: bc00c600 e200ec00 f6000001 10011a01 ?…………….
00000040: 2a012e01 38013801 44015401 54015401 ?*…8.8.D.T.T.T.
00000050: 54015401 54015401 64016401 64016e01 ?T.T.T.T.d.d.d.n.
00000060: 78019401 9e01ae01 ca019eb2 1d7874c9 ?x…………xt.
00000070: 5d4d85b9 d1422e77 c1620100 01008002 ?]M…B.w.b……
00000080: 0000ffff ffff8000 00000000 00000000 ?…………….
00000090: 00000000 00000000 00000000 00000000 ?…………….
000000A0: 00000000 00000000 00000000 80010000 ?…………….
000000B0: 00000000 ffffffff 00020000 7e000000 ?…………~…
000000C0: c6000000 01007e00 0000c600 00000100 ?……~………
000000D0: 0000355a f94bc493 9149ac29 044140d0 ?..5Z.K…I.).A@.
000000E0: 3b1f7e00 0000b100 00002500 00000000 ?;.~…….%…..
000000F0: 00000000 00008400 00003601 00002500 ?……….6…%.
00000100: 0567c9fb b5520346 853c86ad b3f47661 ?.g…R.F.<….va
00000110: 00000000 00000000 0000018e a4cb618f ?…………..a.
00000120: 414c90c3 68f1a4fd 0d810800 00007e00 ?AL..h………~.
00000130: 0000c600 00000100 44004c00 47005000 ?……..D.L.G.P.
00000140: 4f005300 cf6c06e9 4b9b3649 a11c2b70 ?O.S..l..K.6I..+p
00000150: dbebb977 355af94b c4939149 ac290441 ?…w5Z.K…I.).A
00000160: 40d03b1f 00000000 00000000 00000000 ?@.;………….
00000170: 00000000 00000000 00000000 00000000 ?…………….
00000180: 00000000 00000000 00000000 00000000 ?…………….
00000190: 00000000 7e000000 b1000000 25003804 ?….~…….%.8.
000001A0: 48829a28 104c95f3 4b9d6a91 ab480000 ?H..(.L..K.j..H..
000001B0: 00000000 00000000 00000000 00000000 ?…………….
000001C0: 00000000 00000000 0000???????????????……….
BindingID = 781db29e-c974-4d5d-85b9-d1422e77c162 FileGroupId = 1
FileIdProp = 1 Size = 640 MaxSize = 65535
Growth = 128 Perf = 0 BackupLsn = (0:0:0)
MaxLsn = (126:198:1) FirstLsn = (126:177:37) OldestRestoredLsn = (0:0:0)
FirstUpdateLsn = (0:0:0) FirstNonloggedUpdateLsn = [NULL] CreateLsn = (0:0:0)
DifferentialBaseLsn = (132:310:37) DifferentialBaseGuid = fbc96705-52b5-4603-853c-86adb3f47661
MinSize = 384 Status = 0 UserShrinkSize = 65535
DBCC 执行完毕。如果 DBCC 输出了错误信息，请与系统管理员联系。
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