昨天我只是將數據庫附加到SQL2012，然後各個數據庫都做了收縮事務日志的操作
兼容級別這些都沒有改
再附加回SQL2005的時候就報錯
在SQL2012裡附加，確實是90級別，但是在SQL2005死活附加不上
備份數據庫再還原也是一樣
重建事務日志也是一樣
然後我做了一個實驗，檢查一下附加到SQL2012的數據庫和附加到SQL2005的數據庫，兩個數據庫的文件頭有什麼不同
注意：兩個數據庫的兼容級別都是90，附加到SQL2012之後我也沒有動過兼容級別！！
我們用同一個數據庫，分別附加到SQL2005上和SQL2012上，看一下附加之後數據庫的文件頭有沒有改變
這個數據庫的兼容級別是90的
附加到SQL2012之後，我也不改變他的兼容級別
查看文件頭的SQL語句如下，實際上就是數據庫的第0頁：
復制代碼 代碼如下:
DBCC TRACEON(3604,-1)
DBCC PAGE(dlgpos,1,0,3)
在SQL2012裡和SQL2005裡都執行一下
將結果復制粘貼到一個新建的記事本裡，命名好
復制代碼 代碼如下:
DBCC 執行完畢。如果 DBCC 輸出了錯誤信息，請與系統管理員聯系。
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 執行完畢。如果 DBCC 輸出了錯誤信息，請與系統管理員聯系。
SQL2012文件頭
復制代碼 代碼如下:
DBCC 執行完畢。如果 DBCC 輸出了錯誤信息，請與系統管理員聯系。
PAGE: (1:0)
BUFFER:
BUF @0x0456ACA8
bpage = 0x187CA000 bhash = 0x00000000 bpageno = (1:0)
bdbid = 9 breferences = 0 bcputicks = 0
bsampleCount = 0 bUse1 = 8145 bstat = 0x9
blog = 0x21215a7a bnext = 0x00000000
PAGE HEADER:
Page @0x187CA000
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 = 3302
m_reservedCnt = 0 m_lsn = (141:733:159) m_xactReserved = 0
m_xdesId = (0:0) m_ghostRecCnt = 0 m_tornBits = 426768658
DB Frag ID = 1
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
Record Size = 458
Memory Dump @0x1019CB1C
00000000: 30000800 00000000 2d000000 00000000 2c007a00 0.......-.......,.z.
00000014: 7a007c00 7e008200 86008a00 8e009800 a200ac00 z.|.~...............
00000028: ac00b000 b400b800 bc00c600 e200ec00 f6000001 ....................
0000003C: 10011a01 2a012e01 38013801 44015401 54015401 ....*...8.8.D.T.T.T.
00000050: 54015401 54015401 64016401 64016e01 78019401 T.T.T.T.d.d.d.n.x...
00000064: 9e01ae01 ca019eb2 1d7874c9 5d4d85b9 d1422e77 .........xt.]M...B.w
00000078: c1620100 01000003 0000ffff ffff8000 00000000 .b..................
0000008C: 00000000 00000000 00000000 00000000 00000000 ....................
000000A0: 00000000 00000000 00000000 80010000 00000000 ....................
000000B4: ffffffff 00020000 7e000000 c6000000 01007e00 ........~.........~.
000000C8: 0000c600 00000100 0000355a f94bc493 9149ac29 ..........5Z.K...I.)
000000DC: 044140d0 3b1f7e00 0000b100 00002500 00000000 .A@.;.~.......%.....
000000F0: 00000000 00008400 00003601 00002500 0567c9fb ..........6...%..g..
00000104: b5520346 853c86ad b3f47661 00000000 00000000 .R.F.<....va........
00000118: 0000018e a4cb618f 414c90c3 68f1a4fd 0d810800 ......a.AL..h.......
0000012C: 00007e00 0000c600 00000100 44004c00 47005000 ..~.........D.L.G.P.
00000140: 4f005300 cf6c06e9 4b9b3649 a11c2b70 dbebb977 O.S..l..K.6I..+p...w
00000154: 355af94b c4939149 ac290441 40d03b1f 00000000 5Z.K...I.).A@.;.....
00000168: 00000000 00000000 00000000 00000000 00000000 ....................
0000017C: 00000000 00000000 00000000 00000000 00000000 ....................
00000190: 00000000 7e000000 b1000000 25003804 48829a28 ....~.......%.8.H..(
000001A4: 104c95f3 4b9d6a91 ab480000 00000000 00000000 .L..K.j..H..........
000001B8: 00000000 00000000 00000000 00000000 0000 ..................
BindingID = 781db29e-c974-4d5d-85b9-d1422e77c162 FileIdProp = 1
FileGroupId = 1 Size = 768 MaxSize = 65535
Growth = 128 Perf = 0 BackupLsn = (0:0:0)
FirstUpdateLsn = (0:0:0) OldestRestoredLsn = (0:0:0) FirstNonloggedUpdateLsn = [NULL]
MinSize = 384 Status = 0 UserShrinkSize = 65535
SectorSize = 512 MaxLsn = (126:198:1) FirstLsn = (126:177:37)
CreateLsn = (0:0:0) DifferentialBaseLsn = (132:310:37)
DifferentialBaseGuid = fbc96705-52b5-4603-853c-86adb3f47661 FileOfflineLsn = (0:0:0)
FileIdGuid = cba48e01-8f61-4c41-90c3-68f1a4fd0d81 RestoreStatus = 8
RestoreRedoStartLsn = (126:198:1) RestoreSourceGuid = e9066ccf-9b4b-4936-a11c-2b70dbebb977
HardenedSkipLsn = [NULL] ReplTxfTruncationLsn = [NULL] TxfBackupLsn = [NULL]
FstrContainerSize = [NULL] MaxLsnBranchId = 4bf95a35-93c4-4991-ac29-044140d03b1f
SecondaryRedoStartLsn = [NULL] SecondaryDifferentialBaseLsn = [NULL]
ReadOnlyLsn = (0:0:0) ReadWriteLsn = (0:0:0)
RestoreDifferentialBaseLsn = (126:177:37)
RestoreDifferentialBaseGuid = 82480438-289a-4c10-95f3-4b9d6a91ab48
RestorePathOrigin
hex (dec) = 0x00000000:00000000:0000 (0:0:0)
m_guid = 00000000-0000-0000-0000-000000000000
DatabaseEncryptionFileState = [NULL]FCBFileDEK = [NULL]
DBCC 執行完畢。如果 DBCC 輸出了錯誤信息，請與系統管理員聯系。
可以用Beyond Compare這個軟件比較一下兩者的文件頭的差異
Beyond Compare這個軟件會把兩個txt文件中的相同點用藍色標記出來，不同點用紅色標記出來
當附加到SQL2012之後，數據庫的文件頭已經走樣了，就算你沒有動過兼容級別，這也是造成曾經附加到SQL2012的數據庫
再也附加不上SQL2005上的原因
可以看到SQL2012的數據庫記錄的信息比SQL2005詳細多了，多了很多內容
也可以用下面的SQL語句看文件頭的內容，不過信息比較少
1 DBCC fileheader('DLGPOS')
總結
上面的實驗證明了，當你將一個SQL2005的數據庫附加到SQL2012上的時候，SQL2012馬上改變數據庫的文件頭
就算你不動數據庫兼容級別，實際上數據庫的信息已經改變了（這裡指文件頭信息）
所以你死活附加不回去SQL2005了
以後不要輕易附加數據庫到SQL2012上，不然的話。。。。。。
補充一下
