恢复SQL Server被误删除的数据

时间:2023-03-08 16:09:52
恢复SQL Server被误删除的数据

恢复SQL Server被误删除的数据

恢复SQL Server被误删除的数据(再扩展)

地址:http://www.cnblogs.com/lyhabc/p/4620764.html

曾经想实现Log Explorer for SQL Server的功能,利用ldf里面的日志来还原误删除的数据

这里有一篇文章做到了,不过似乎不是所有的数据类型都支持

以下为译文:http://raresql.com/2011/10/22/how-to-recover-deleted-data-from-sql-sever/

在我使用SQLSERVER的这些年里面,大部分人都会问我一个问题:“能不能恢复被删除的数据??”

现在,从SQLSERVER2005 或以上版本能很容易能够恢复被删除的数据

(注意:这个脚本能恢复下面的数据类型的数据 而且兼容CS 排序规则)

  • image
  • text
  • uniqueidentifier
  • tinyint
  • smallint
  • int
  • smalldatetime
  • real
  • money
  • datetime
  • float
  • sql_variant
  • ntext
  • bit
  • decimal
  • numeric
  • smallmoney
  • bigint
  • varbinary
  • varchar
  • binary
  • char
  • timestamp
  • nvarchar
  • nchar
  • xml
  • sysname

让我来用demo来解释一下我是怎么做到的

USE master
GO
--创建数据库
CREATE DATABASE test
GO USE [test]
GO --创建表
CREATE TABLE [dbo].[aa](
[id] [int] IDENTITY(1,1) NOT NULL,
[NAME] [nvarchar](200) NULL
) ON [PRIMARY]
GO --插入测试数据
INSERT [dbo].[aa]
( [NAME] )
SELECT '你好'
GO --删除数据
Delete from aa
Go --验证数据是否已经删除
Select * from aa
Go

现在你需要创建一个存储过程来恢复你的数据

-- Script Name: Recover_Deleted_Data_Proc
-- Script Type : Recovery Procedure
-- Develop By: Muhammad Imran
-- Date Created: 15 Oct 2011
-- Modify Date: 22 Aug 2012
-- Version : 3.1
-- Notes : Included BLOB data types for recovery.& Compatibile with Default , CS collation , Arabic_CI_AS. CREATE PROCEDURE Recover_Deleted_Data_Proc
@Database_Name NVARCHAR(MAX) ,
@SchemaName_n_TableName NVARCHAR(MAX) ,
@Date_From DATETIME = '1900/01/01' ,
@Date_To DATETIME = '9999/12/31'
AS
DECLARE @RowLogContents VARBINARY(8000)
DECLARE @TransactionID NVARCHAR(MAX)
DECLARE @AllocUnitID BIGINT
DECLARE @AllocUnitName NVARCHAR(MAX)
DECLARE @SQL NVARCHAR(MAX)
DECLARE @Compatibility_Level INT SELECT @Compatibility_Level = dtb.compatibility_level
FROM master.sys.databases AS dtb
WHERE dtb.name = @Database_Name IF ISNULL(@Compatibility_Level, 0) <= 80
BEGIN
RAISERROR('The compatibility level should be equal to or greater SQL SERVER 2005 (90)',16,1)
RETURN
END IF ( SELECT COUNT(*)
FROM INFORMATION_SCHEMA.TABLES
WHERE [TABLE_SCHEMA] + '.' + [TABLE_NAME] = @SchemaName_n_TableName
) = 0
BEGIN
RAISERROR('Could not found the table in the defined database',16,1)
RETURN
END DECLARE @bitTable TABLE
(
[ID] INT ,
[Bitvalue] INT
)
--Create table to set the bit position of one byte. INSERT INTO @bitTable
SELECT 0 ,
2
UNION ALL
SELECT 1 ,
2
UNION ALL
SELECT 2 ,
4
UNION ALL
SELECT 3 ,
8
UNION ALL
SELECT 4 ,
16
UNION ALL
SELECT 5 ,
32
UNION ALL
SELECT 6 ,
64
UNION ALL
SELECT 7 ,
128 --Create table to collect the row data.
DECLARE @DeletedRecords TABLE
(
[Row ID] INT IDENTITY(1, 1) ,
[RowLogContents] VARBINARY(8000) ,
[AllocUnitID] BIGINT ,
[Transaction ID] NVARCHAR(MAX) ,
[FixedLengthData] SMALLINT ,
[TotalNoOfCols] SMALLINT ,
[NullBitMapLength] SMALLINT ,
[NullBytes] VARBINARY(8000) ,
[TotalNoofVarCols] SMALLINT ,
[ColumnOffsetArray] VARBINARY(8000) ,
[VarColumnStart] SMALLINT ,
[Slot ID] INT ,
[NullBitMap] VARCHAR(MAX)
)
--Create a common table expression to get all the row data plus how many bytes we have for each row.
;
WITH RowData
AS ( SELECT [RowLog Contents 0] AS [RowLogContents] ,
[AllocUnitID] AS [AllocUnitID] ,
[Transaction ID] AS [Transaction ID] --[Fixed Length Data] = Substring (RowLog content 0, Status Bit A+ Status Bit B + 1,2 bytes)
,
CONVERT(SMALLINT, CONVERT(BINARY(2), REVERSE(SUBSTRING([RowLog Contents 0],
2 + 1, 2)))) AS [FixedLengthData] --@FixedLengthData -- [TotalnoOfCols] = Substring (RowLog content 0, [Fixed Length Data] + 1,2 bytes)
,
CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([RowLog Contents 0],
CONVERT(SMALLINT, CONVERT(BINARY(2), REVERSE(SUBSTRING([RowLog Contents 0],
2 + 1, 2)))) + 1,
2)))) AS [TotalNoOfCols] --[NullBitMapLength]=ceiling([Total No of Columns] /8.0)
,
CONVERT(INT, CEILING(CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([RowLog Contents 0],
CONVERT(SMALLINT, CONVERT(BINARY(2), REVERSE(SUBSTRING([RowLog Contents 0],
2 + 1, 2)))) + 1,
2)))) / 8.0)) AS [NullBitMapLength] --[Null Bytes] = Substring (RowLog content 0, Status Bit A+ Status Bit B + [Fixed Length Data] +1, [NullBitMapLength] )
,
SUBSTRING([RowLog Contents 0],
CONVERT(SMALLINT, CONVERT(BINARY(2), REVERSE(SUBSTRING([RowLog Contents 0],
2 + 1, 2)))) + 3,
CONVERT(INT, CEILING(CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([RowLog Contents 0],
CONVERT(SMALLINT, CONVERT(BINARY(2), REVERSE(SUBSTRING([RowLog Contents 0],
2 + 1, 2)))) + 1,
2)))) / 8.0))) AS [NullBytes] --[TotalNoofVarCols] = Substring (RowLog content 0, Status Bit A+ Status Bit B + [Fixed Length Data] +1, [Null Bitmap length] + 2 )
,
( CASE WHEN SUBSTRING([RowLog Contents 0], 1, 1) IN (
0x10, 0x30, 0x70 )
THEN CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([RowLog Contents 0],
CONVERT(SMALLINT, CONVERT(BINARY(2), REVERSE(SUBSTRING([RowLog Contents 0],
2 + 1, 2)))) + 3
+ CONVERT(INT, CEILING(CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([RowLog Contents 0],
CONVERT(SMALLINT, CONVERT(BINARY(2), REVERSE(SUBSTRING([RowLog Contents 0],
2 + 1, 2)))) + 1,
2)))) / 8.0)), 2))))
ELSE NULL
END ) AS [TotalNoofVarCols] --[ColumnOffsetArray]= Substring (RowLog content 0, Status Bit A+ Status Bit B + [Fixed Length Data] +1, [Null Bitmap length] + 2 , [TotalNoofVarCols]*2 )
,
( CASE WHEN SUBSTRING([RowLog Contents 0], 1, 1) IN (
0x10, 0x30, 0x70 )
THEN SUBSTRING([RowLog Contents 0],
CONVERT(SMALLINT, CONVERT(BINARY(2), REVERSE(SUBSTRING([RowLog Contents 0],
2 + 1, 2)))) + 3
+ CONVERT(INT, CEILING(CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([RowLog Contents 0],
CONVERT(SMALLINT, CONVERT(BINARY(2), REVERSE(SUBSTRING([RowLog Contents 0],
2 + 1, 2)))) + 1,
2)))) / 8.0))
+ 2,
( CASE WHEN SUBSTRING([RowLog Contents 0],
1, 1) IN ( 0x10,
0x30, 0x70 )
THEN CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([RowLog Contents 0],
CONVERT(SMALLINT, CONVERT(BINARY(2), REVERSE(SUBSTRING([RowLog Contents 0],
2 + 1, 2)))) + 3
+ CONVERT(INT, CEILING(CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([RowLog Contents 0],
CONVERT(SMALLINT, CONVERT(BINARY(2), REVERSE(SUBSTRING([RowLog Contents 0],
2 + 1, 2)))) + 1,
2)))) / 8.0)), 2))))
ELSE NULL
END ) * 2)
ELSE NULL
END ) AS [ColumnOffsetArray] -- Variable column Start = Status Bit A+ Status Bit B + [Fixed Length Data] + [Null Bitmap length] + 2+([TotalNoofVarCols]*2)
,
CASE WHEN SUBSTRING([RowLog Contents 0], 1, 1) IN (
0x10, 0x30, 0x70 )
THEN ( CONVERT(SMALLINT, CONVERT(BINARY(2), REVERSE(SUBSTRING([RowLog Contents 0],
2 + 1, 2)))) + 4
+ CONVERT(INT, CEILING(CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([RowLog Contents 0],
CONVERT(SMALLINT, CONVERT(BINARY(2), REVERSE(SUBSTRING([RowLog Contents 0],
2 + 1, 2)))) + 1,
2)))) / 8.0))
+ ( ( CASE WHEN SUBSTRING([RowLog Contents 0],
1, 1) IN ( 0x10,
0x30, 0x70 )
THEN CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([RowLog Contents 0],
CONVERT(SMALLINT, CONVERT(BINARY(2), REVERSE(SUBSTRING([RowLog Contents 0],
2 + 1, 2)))) + 3
+ CONVERT(INT, CEILING(CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([RowLog Contents 0],
CONVERT(SMALLINT, CONVERT(BINARY(2), REVERSE(SUBSTRING([RowLog Contents 0],
2 + 1, 2)))) + 1,
2)))) / 8.0)), 2))))
ELSE NULL
END ) * 2 ) )
ELSE NULL
END AS [VarColumnStart] ,
[Slot ID]
FROM sys.fn_dblog(NULL, NULL)
WHERE AllocUnitId IN (
SELECT [Allocation_unit_id]
FROM sys.allocation_units allocunits
INNER JOIN sys.partitions partitions ON ( allocunits.type IN (
1, 3 )
AND partitions.hobt_id = allocunits.container_id
)
OR ( allocunits.type = 2
AND partitions.partition_id = allocunits.container_id
)
WHERE object_id = OBJECT_ID(''
+ @SchemaName_n_TableName
+ '') )
AND Context IN ( 'LCX_MARK_AS_GHOST', 'LCX_HEAP' )
AND Operation IN ( 'LOP_DELETE_ROWS' )
AND SUBSTRING([RowLog Contents 0], 1, 1) IN ( 0x10,
0x30, 0x70 ) /*Use this subquery to filter the date*/
AND [TRANSACTION ID] IN (
SELECT DISTINCT
[TRANSACTION ID]
FROM sys.fn_dblog(NULL, NULL)
WHERE Context IN ( 'LCX_NULL' )
AND Operation IN ( 'LOP_BEGIN_XACT' )
AND [Transaction Name] IN ( 'DELETE',
'user_transaction' )
AND CONVERT(NVARCHAR(11), [Begin Time]) BETWEEN @Date_From
AND
@Date_To )
), --Use this technique to repeate the row till the no of bytes of the row.
N1 ( n )
AS ( SELECT 1
UNION ALL
SELECT 1
),
N2 ( n )
AS ( SELECT 1
FROM N1 AS X ,
N1 AS Y
),
N3 ( n )
AS ( SELECT 1
FROM N2 AS X ,
N2 AS Y
),
N4 ( n )
AS ( SELECT ROW_NUMBER() OVER ( ORDER BY X.n )
FROM N3 AS X ,
N3 AS Y
)
INSERT INTO @DeletedRecords
SELECT RowLogContents ,
[AllocUnitID] ,
[Transaction ID] ,
[FixedLengthData] ,
[TotalNoOfCols] ,
[NullBitMapLength] ,
[NullBytes] ,
[TotalNoofVarCols] ,
[ColumnOffsetArray] ,
[VarColumnStart] ,
[Slot ID]
---Get the Null value against each column (1 means null zero means not null)
,
[NullBitMap] = ( REPLACE(STUFF(( SELECT
','
+ ( CASE
WHEN [ID] = 0
THEN CONVERT(NVARCHAR(1), ( SUBSTRING(NullBytes,
n, 1) % 2 ))
ELSE CONVERT(NVARCHAR(1), ( ( SUBSTRING(NullBytes,
n, 1)
/ [Bitvalue] )
% 2 ))
END ) --as [nullBitMap]
FROM N4 AS Nums
JOIN RowData AS C ON n <= NullBitMapLength
CROSS JOIN @bitTable
WHERE
C.[RowLogContents] = D.[RowLogContents]
ORDER BY [RowLogContents] ,
n ASC
FOR
XML PATH('')
), 1, 1, ''), ',', '') )
FROM RowData D IF ( SELECT COUNT(*)
FROM @DeletedRecords
) = 0
BEGIN
RAISERROR('There is no data in the log as per the search criteria',16,1)
RETURN
END DECLARE @ColumnNameAndData TABLE
(
[Row ID] INT ,
[Rowlogcontents] VARBINARY(MAX) ,
[NAME] SYSNAME ,
[nullbit] SMALLINT ,
[leaf_offset] SMALLINT ,
[length] SMALLINT ,
[system_type_id] TINYINT ,
[bitpos] TINYINT ,
[xprec] TINYINT ,
[xscale] TINYINT ,
[is_null] INT ,
[Column value Size] INT ,
[Column Length] INT ,
[hex_Value] VARBINARY(MAX) ,
[Slot ID] INT ,
[Update] INT
) --Create common table expression and join it with the rowdata table
-- to get each column details
/*This part is for variable data columns*/
--@RowLogContents,
--(col.columnOffValue - col.columnLength) + 1,
--col.columnLength
--)
INSERT INTO @ColumnNameAndData
SELECT [Row ID] ,
Rowlogcontents ,
NAME ,
cols.leaf_null_bit AS nullbit ,
leaf_offset ,
ISNULL(syscolumns.length, cols.max_length) AS [length] ,
cols.system_type_id ,
cols.leaf_bit_position AS bitpos ,
ISNULL(syscolumns.xprec, cols.precision) AS xprec ,
ISNULL(syscolumns.xscale, cols.scale) AS xscale ,
SUBSTRING([nullBitMap], cols.leaf_null_bit, 1) AS is_null ,
( CASE WHEN leaf_offset < 1
AND SUBSTRING([nullBitMap], cols.leaf_null_bit,
1) = 0
THEN ( CASE WHEN CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* leaf_offset
* -1 ) - 1, 2)))) > 30000
THEN CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* leaf_offset
* -1 ) - 1, 2))))
- POWER(2, 15)
ELSE CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* leaf_offset
* -1 ) - 1, 2))))
END )
END ) AS [Column value Size] ,
( CASE WHEN leaf_offset < 1
AND SUBSTRING([nullBitMap], cols.leaf_null_bit,
1) = 0
THEN ( CASE WHEN CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* leaf_offset
* -1 ) - 1, 2)))) > 30000
AND ISNULL(NULLIF(CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* ( ( leaf_offset
* -1 ) - 1 ) )
- 1, 2)))), 0),
[varColumnStart]) < 30000
THEN ( CASE WHEN [System_type_id] IN (
35, 34, 99 ) THEN 16
ELSE 24
END )
WHEN CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* leaf_offset
* -1 ) - 1, 2)))) > 30000
AND ISNULL(NULLIF(CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* ( ( leaf_offset
* -1 ) - 1 ) )
- 1, 2)))), 0),
[varColumnStart]) > 30000
THEN ( CASE WHEN [System_type_id] IN (
35, 34, 99 ) THEN 16
ELSE 24
END ) --24
WHEN CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* leaf_offset
* -1 ) - 1, 2)))) < 30000
AND ISNULL(NULLIF(CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* ( ( leaf_offset
* -1 ) - 1 ) )
- 1, 2)))), 0),
[varColumnStart]) < 30000
THEN ( CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* leaf_offset
* -1 ) - 1, 2))))
- ISNULL(NULLIF(CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* ( ( leaf_offset
* -1 ) - 1 ) )
- 1, 2)))), 0),
[varColumnStart]) )
WHEN CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* leaf_offset
* -1 ) - 1, 2)))) < 30000
AND ISNULL(NULLIF(CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* ( ( leaf_offset
* -1 ) - 1 ) )
- 1, 2)))), 0),
[varColumnStart]) > 30000
THEN POWER(2, 15)
+ CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* leaf_offset
* -1 ) - 1, 2))))
- ISNULL(NULLIF(CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* ( ( leaf_offset
* -1 ) - 1 ) )
- 1, 2)))), 0),
[varColumnStart])
END )
END ) AS [Column Length] ,
( CASE WHEN SUBSTRING([nullBitMap], cols.leaf_null_bit, 1) = 1
THEN NULL
ELSE SUBSTRING(Rowlogcontents,
( ( CASE WHEN CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* leaf_offset
* -1 ) - 1, 2)))) > 30000
THEN CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* leaf_offset
* -1 ) - 1, 2))))
- POWER(2, 15)
ELSE CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* leaf_offset
* -1 ) - 1, 2))))
END )
- ( CASE WHEN CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* leaf_offset
* -1 ) - 1, 2)))) > 30000
AND ISNULL(NULLIF(CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* ( ( leaf_offset
* -1 ) - 1 ) )
- 1, 2)))), 0),
[varColumnStart]) < 30000
THEN ( CASE
WHEN [System_type_id] IN (
35, 34, 99 )
THEN 16
ELSE 24
END ) --24
WHEN CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* leaf_offset
* -1 ) - 1, 2)))) > 30000
AND ISNULL(NULLIF(CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* ( ( leaf_offset
* -1 ) - 1 ) )
- 1, 2)))), 0),
[varColumnStart]) > 30000
THEN ( CASE
WHEN [System_type_id] IN (
35, 34, 99 )
THEN 16
ELSE 24
END ) --24
WHEN CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* leaf_offset
* -1 ) - 1, 2)))) < 30000
AND ISNULL(NULLIF(CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* ( ( leaf_offset
* -1 ) - 1 ) )
- 1, 2)))), 0),
[varColumnStart]) < 30000
THEN CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* leaf_offset
* -1 ) - 1, 2))))
- ISNULL(NULLIF(CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* ( ( leaf_offset
* -1 ) - 1 ) )
- 1, 2)))), 0),
[varColumnStart])
WHEN CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* leaf_offset
* -1 ) - 1, 2)))) < 30000
AND ISNULL(NULLIF(CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* ( ( leaf_offset
* -1 ) - 1 ) )
- 1, 2)))), 0),
[varColumnStart]) > 30000
THEN POWER(2, 15)
+ CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* leaf_offset
* -1 ) - 1, 2))))
- ISNULL(NULLIF(CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* ( ( leaf_offset
* -1 ) - 1 ) )
- 1, 2)))), 0),
[varColumnStart])
END ) ) + 1,
( CASE WHEN CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* leaf_offset
* -1 ) - 1, 2)))) > 30000
AND ISNULL(NULLIF(CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* ( ( leaf_offset
* -1 ) - 1 ) )
- 1, 2)))), 0),
[varColumnStart]) < 30000
THEN ( CASE WHEN [System_type_id] IN (
35, 34, 99 )
THEN 16
ELSE 24
END ) --24
WHEN CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* leaf_offset
* -1 ) - 1, 2)))) > 30000
AND ISNULL(NULLIF(CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* ( ( leaf_offset
* -1 ) - 1 ) )
- 1, 2)))), 0),
[varColumnStart]) > 30000
THEN ( CASE WHEN [System_type_id] IN (
35, 34, 99 )
THEN 16
ELSE 24
END ) --24
WHEN CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* leaf_offset
* -1 ) - 1, 2)))) < 30000
AND ISNULL(NULLIF(CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* ( ( leaf_offset
* -1 ) - 1 ) )
- 1, 2)))), 0),
[varColumnStart]) < 30000
THEN ABS(CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* leaf_offset
* -1 ) - 1, 2))))
- ISNULL(NULLIF(CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* ( ( leaf_offset
* -1 ) - 1 ) )
- 1, 2)))), 0),
[varColumnStart]))
WHEN CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* leaf_offset
* -1 ) - 1, 2)))) < 30000
AND ISNULL(NULLIF(CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* ( ( leaf_offset
* -1 ) - 1 ) )
- 1, 2)))), 0),
[varColumnStart]) > 30000
THEN POWER(2, 15)
+ CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* leaf_offset
* -1 ) - 1, 2))))
- ISNULL(NULLIF(CONVERT(INT, CONVERT(BINARY(2), REVERSE(SUBSTRING([ColumnOffsetArray],
( 2
* ( ( leaf_offset
* -1 ) - 1 ) )
- 1, 2)))), 0),
[varColumnStart])
END ))
END ) AS hex_Value ,
[Slot ID] ,
0
FROM @DeletedRecords A
INNER JOIN sys.allocation_units allocunits ON A.[AllocUnitId] = allocunits.[Allocation_Unit_Id]
INNER JOIN sys.partitions partitions ON ( allocunits.type IN (
1, 3 )
AND partitions.hobt_id = allocunits.container_id
)
OR ( allocunits.type = 2
AND partitions.partition_id = allocunits.container_id
)
INNER JOIN sys.system_internals_partition_columns cols ON cols.partition_id = partitions.partition_id
LEFT OUTER JOIN syscolumns ON syscolumns.id = partitions.object_id
AND syscolumns.colid = cols.partition_column_id
WHERE leaf_offset < 0
UNION
/*This part is for fixed data columns*/
SELECT [Row ID] ,
Rowlogcontents ,
NAME ,
cols.leaf_null_bit AS nullbit ,
leaf_offset ,
ISNULL(syscolumns.length, cols.max_length) AS [length] ,
cols.system_type_id ,
cols.leaf_bit_position AS bitpos ,
ISNULL(syscolumns.xprec, cols.precision) AS xprec ,
ISNULL(syscolumns.xscale, cols.scale) AS xscale ,
SUBSTRING([nullBitMap], cols.leaf_null_bit, 1) AS is_null ,
( SELECT TOP 1
ISNULL(SUM(CASE WHEN C.leaf_offset > 1
THEN max_length
ELSE 0
END), 0)
FROM sys.system_internals_partition_columns C
WHERE cols.partition_id = C.partition_id
AND C.leaf_null_bit < cols.leaf_null_bit
) + 5 AS [Column value Size] ,
syscolumns.length AS [Column Length] ,
CASE WHEN SUBSTRING([nullBitMap], cols.leaf_null_bit, 1) = 1
THEN NULL
ELSE SUBSTRING(Rowlogcontents,
( SELECT TOP 1
ISNULL(SUM(CASE
WHEN C.leaf_offset > 1
AND C.leaf_bit_position = 0
THEN max_length
ELSE 0
END), 0)
FROM sys.system_internals_partition_columns C
WHERE cols.partition_id = C.partition_id
AND C.leaf_null_bit < cols.leaf_null_bit
) + 5, syscolumns.length)
END AS hex_Value ,
[Slot ID] ,
0
FROM @DeletedRecords A
INNER JOIN sys.allocation_units allocunits ON A.[AllocUnitId] = allocunits.[Allocation_Unit_Id]
INNER JOIN sys.partitions partitions ON ( allocunits.type IN (
1, 3 )
AND partitions.hobt_id = allocunits.container_id
)
OR ( allocunits.type = 2
AND partitions.partition_id = allocunits.container_id
)
INNER JOIN sys.system_internals_partition_columns cols ON cols.partition_id = partitions.partition_id
LEFT OUTER JOIN syscolumns ON syscolumns.id = partitions.object_id
AND syscolumns.colid = cols.partition_column_id
WHERE leaf_offset > 0
ORDER BY nullbit DECLARE @BitColumnByte AS INT
SELECT @BitColumnByte = CONVERT(INT, CEILING(COUNT(*) / 8.0))
FROM @ColumnNameAndData
WHERE [System_Type_id] = 104;
WITH N1 ( n )
AS ( SELECT 1
UNION ALL
SELECT 1
),
N2 ( n )
AS ( SELECT 1
FROM N1 AS X ,
N1 AS Y
),
N3 ( n )
AS ( SELECT 1
FROM N2 AS X ,
N2 AS Y
),
N4 ( n )
AS ( SELECT ROW_NUMBER() OVER ( ORDER BY X.n )
FROM N3 AS X ,
N3 AS Y
),
CTE
AS ( SELECT RowLogContents ,
[nullbit] ,
[BitMap] = CONVERT(VARBINARY(1), CONVERT(INT, SUBSTRING(( REPLACE(STUFF(( SELECT
','
+ ( CASE
WHEN [ID] = 0
THEN CONVERT(NVARCHAR(1), ( SUBSTRING(hex_Value,
n, 1) % 2 ))
ELSE CONVERT(NVARCHAR(1), ( ( SUBSTRING(hex_Value,
n, 1)
/ [Bitvalue] )
% 2 ))
END ) --as [nullBitMap]
FROM
N4 AS Nums
JOIN @ColumnNameAndData
AS C ON n <= @BitColumnByte
AND [System_Type_id] = 104
AND bitpos = 0
CROSS JOIN @bitTable
WHERE
C.[RowLogContents] = D.[RowLogContents]
ORDER BY [RowLogContents] ,
n ASC
FOR
XML
PATH('')
), 1, 1, ''),
',', '') ),
bitpos + 1, 1)))
FROM @ColumnNameAndData D
WHERE [System_Type_id] = 104
)
UPDATE A
SET [hex_Value] = [BitMap]
FROM @ColumnNameAndData A
INNER JOIN CTE B ON A.[RowLogContents] = B.[RowLogContents]
AND A.[nullbit] = B.[nullbit] /**************Check for BLOB DATA TYPES******************************/
DECLARE @Fileid INT
DECLARE @Pageid INT
DECLARE @Slotid INT
DECLARE @CurrentLSN INT
DECLARE @LinkID INT
DECLARE @Context VARCHAR(50)
DECLARE @ConsolidatedPageID VARCHAR(MAX)
DECLARE @LCX_TEXT_MIX VARBINARY(MAX) DECLARE @temppagedata TABLE
(
[ParentObject] SYSNAME ,
[Object] SYSNAME ,
[Field] SYSNAME ,
[Value] SYSNAME
) DECLARE @pagedata TABLE
(
[Page ID] SYSNAME ,
[File IDS] INT ,
[Page IDS] INT ,
[AllocUnitId] BIGINT ,
[ParentObject] SYSNAME ,
[Object] SYSNAME ,
[Field] SYSNAME ,
[Value] SYSNAME
) DECLARE @ModifiedRawData TABLE
(
[ID] INT IDENTITY(1, 1) ,
[PAGE ID] VARCHAR(MAX) ,
[FILE IDS] INT ,
[PAGE IDS] INT ,
[Slot ID] INT ,
[AllocUnitId] BIGINT ,
[RowLog Contents 0_var] VARCHAR(MAX) ,
[RowLog Length] VARCHAR(50) ,
[RowLog Len] INT ,
[RowLog Contents 0] VARBINARY(MAX) ,
[Link ID] INT DEFAULT ( 0 ) ,
[Update] INT
) DECLARE Page_Data_Cursor CURSOR
FOR
/*We need to filter LOP_MODIFY_ROW,LOP_MODIFY_COLUMNS from log for deleted records of BLOB data type& Get its Slot No, Page ID & AllocUnit ID*/
SELECT LTRIM(RTRIM(REPLACE([Description], 'Deallocated', ''))) AS [PAGE ID] ,
[Slot ID] ,
[AllocUnitId] ,
NULL AS [RowLog Contents 0] ,
NULL AS [RowLog Contents 0] ,
Context
FROM sys.fn_dblog(NULL, NULL)
WHERE AllocUnitId IN (
SELECT [Allocation_unit_id]
FROM sys.allocation_units allocunits
INNER JOIN sys.partitions partitions ON ( allocunits.type IN (
1, 3 )
AND partitions.hobt_id = allocunits.container_id
)
OR ( allocunits.type = 2
AND partitions.partition_id = allocunits.container_id
)
WHERE object_id = OBJECT_ID('' + @SchemaName_n_TableName
+ '') )
AND Operation IN ( 'LOP_MODIFY_ROW' )
AND [Context] IN ( 'LCX_PFS' )
AND Description LIKE '%Deallocated%'
/*Use this subquery to filter the date*/
AND [TRANSACTION ID] IN (
SELECT DISTINCT
[TRANSACTION ID]
FROM sys.fn_dblog(NULL, NULL)
WHERE Context IN ( 'LCX_NULL' )
AND Operation IN ( 'LOP_BEGIN_XACT' )
AND [Transaction Name] = 'DELETE'
AND CONVERT(NVARCHAR(11), [Begin Time]) BETWEEN @Date_From
AND
@Date_To )
GROUP BY [Description] ,
[Slot ID] ,
[AllocUnitId] ,
Context
UNION
SELECT [PAGE ID] ,
[Slot ID] ,
[AllocUnitId] ,
SUBSTRING([RowLog Contents 0], 15,
LEN([RowLog Contents 0])) AS [RowLog Contents 0] ,
CONVERT(INT, SUBSTRING([RowLog Contents 0], 7, 2)) ,
Context --,CAST(RIGHT([Current LSN],4) AS INT) AS [Current LSN]
FROM sys.fn_dblog(NULL, NULL)
WHERE AllocUnitId IN (
SELECT [Allocation_unit_id]
FROM sys.allocation_units allocunits
INNER JOIN sys.partitions partitions ON ( allocunits.type IN (
1, 3 )
AND partitions.hobt_id = allocunits.container_id
)
OR ( allocunits.type = 2
AND partitions.partition_id = allocunits.container_id
)
WHERE object_id = OBJECT_ID('' + @SchemaName_n_TableName
+ '') )
AND Context IN ( 'LCX_TEXT_MIX' )
AND Operation IN ( 'LOP_DELETE_ROWS' )
/*Use this subquery to filter the date*/
AND [TRANSACTION ID] IN (
SELECT DISTINCT
[TRANSACTION ID]
FROM sys.fn_dblog(NULL, NULL)
WHERE Context IN ( 'LCX_NULL' )
AND Operation IN ( 'LOP_BEGIN_XACT' )
AND [Transaction Name] = 'DELETE'
AND CONVERT(NVARCHAR(11), [Begin Time]) BETWEEN @Date_From
AND
@Date_To ) /****************************************/ OPEN Page_Data_Cursor FETCH NEXT FROM Page_Data_Cursor INTO @ConsolidatedPageID, @Slotid,
@AllocUnitID, @LCX_TEXT_MIX, @LinkID, @Context WHILE @@FETCH_STATUS = 0
BEGIN
DECLARE @hex_pageid AS VARCHAR(MAX)
/*Page ID contains File Number and page number It looks like 0001:00000130.
In this example 0001 is file Number & 00000130 is Page Number & These numbers are in Hex format*/
SET @Fileid = SUBSTRING(@ConsolidatedPageID, 0,
CHARINDEX(':', @ConsolidatedPageID)) -- Seperate File ID from Page ID SET @hex_pageid = '0x' + SUBSTRING(@ConsolidatedPageID,
CHARINDEX(':',
@ConsolidatedPageID)
+ 1, LEN(@ConsolidatedPageID)) ---Seperate the page ID
SELECT @Pageid = CONVERT(INT, CAST('' AS XML).value('xs:hexBinary(substring(sql:variable("@hex_pageid"),sql:column("t.pos")) )',
'varbinary(max)')) -- Convert Page ID from hex to integer
FROM ( SELECT CASE SUBSTRING(@hex_pageid, 1, 2)
WHEN '0x' THEN 3
ELSE 0
END
) AS t ( pos ) IF @Context = 'LCX_PFS'
BEGIN
DELETE @temppagedata
INSERT INTO @temppagedata
EXEC
( 'DBCC PAGE(' + @DataBase_Name + ', '
+ @fileid + ', ' + @pageid
+ ', 1) with tableresults,no_infomsgs;'
);
INSERT INTO @pagedata
SELECT @ConsolidatedPageID ,
@fileid ,
@pageid ,
@AllocUnitID ,
[ParentObject] ,
[Object] ,
[Field] ,
[Value]
FROM @temppagedata
END
ELSE
IF @Context = 'LCX_TEXT_MIX'
BEGIN
INSERT INTO @ModifiedRawData
SELECT @ConsolidatedPageID ,
@fileid ,
@pageid ,
@Slotid ,
@AllocUnitID ,
NULL ,
0 ,
CONVERT(INT, CONVERT(VARBINARY, REVERSE(SUBSTRING(@LCX_TEXT_MIX,
11, 2)))) ,
@LCX_TEXT_MIX ,
@LinkID ,
0
END
FETCH NEXT FROM Page_Data_Cursor INTO @ConsolidatedPageID, @Slotid,
@AllocUnitID, @LCX_TEXT_MIX, @LinkID, @Context
END CLOSE Page_Data_Cursor
DEALLOCATE Page_Data_Cursor DECLARE @Newhexstring VARCHAR(MAX); --The data is in multiple rows in the page, so we need to convert it into one row as a single hex value.
--This hex value is in string format
INSERT INTO @ModifiedRawData
( [PAGE ID] ,
[FILE IDS] ,
[PAGE IDS] ,
[Slot ID] ,
[AllocUnitId] ,
[RowLog Contents 0_var] ,
[RowLog Length]
)
SELECT [Page ID] ,
[FILE IDS] ,
[PAGE IDS] ,
SUBSTRING([ParentObject],
CHARINDEX('Slot', [ParentObject]) + 4,
( CHARINDEX('Offset', [ParentObject])
- ( CHARINDEX('Slot', [ParentObject]) + 4 ) )
- 2) AS [Slot ID] ,
[AllocUnitId] ,
SUBSTRING(( SELECT REPLACE(STUFF(( SELECT
REPLACE(SUBSTRING([Value],
CHARINDEX(':',
[Value]) + 1,
CHARINDEX('†',
[Value])
- CHARINDEX(':',
[Value])), '†',
'')
FROM @pagedata C
WHERE B.[Page ID] = C.[Page ID]
AND SUBSTRING(B.[ParentObject],
CHARINDEX('Slot',
B.[ParentObject])
+ 4,
( CHARINDEX('Offset',
B.[ParentObject])
- ( CHARINDEX('Slot',
B.[ParentObject])
+ 4 ) )) = SUBSTRING(C.[ParentObject],
CHARINDEX('Slot',
C.[ParentObject])
+ 4,
( CHARINDEX('Offset',
C.[ParentObject])
- ( CHARINDEX('Slot',
C.[ParentObject])
+ 4 ) ))
AND [Object] LIKE '%Memory Dump%'
ORDER BY '0x'
+ LEFT([Value],
CHARINDEX(':',
[Value]) - 1)
FOR
XML PATH('')
), 1, 1, ''), ' ', '')
), 1, 20000) AS [Value] ,
SUBSTRING(( SELECT '0x'
+ REPLACE(STUFF(( SELECT
REPLACE(SUBSTRING([Value],
CHARINDEX(':',
[Value]) + 1,
CHARINDEX('†',
[Value])
- CHARINDEX(':',
[Value])), '†',
'')
FROM
@pagedata C
WHERE
B.[Page ID] = C.[Page ID]
AND SUBSTRING(B.[ParentObject],
CHARINDEX('Slot',
B.[ParentObject])
+ 4,
( CHARINDEX('Offset',
B.[ParentObject])
- ( CHARINDEX('Slot',
B.[ParentObject])
+ 4 ) )) = SUBSTRING(C.[ParentObject],
CHARINDEX('Slot',
C.[ParentObject])
+ 4,
( CHARINDEX('Offset',
C.[ParentObject])
- ( CHARINDEX('Slot',
C.[ParentObject])
+ 4 ) ))
AND [Object] LIKE '%Memory Dump%'
ORDER BY '0x'
+ LEFT([Value],
CHARINDEX(':',
[Value]) - 1)
FOR
XML PATH('')
), 1, 1, ''), ' ', '')
), 7, 4) AS [Length]
FROM @pagedata B
WHERE [Object] LIKE '%Memory Dump%'
GROUP BY [Page ID] ,
[FILE IDS] ,
[PAGE IDS] ,
[ParentObject] ,
[AllocUnitId]--,[Current LSN]
ORDER BY [Slot ID] UPDATE @ModifiedRawData
SET [RowLog Len] = CONVERT(VARBINARY(8000), REVERSE(CAST('' AS XML).value('xs:hexBinary(substring(sql:column("[RowLog Length]"),0))',
'varbinary(Max)')))
FROM @ModifiedRawData
WHERE [LINK ID] = 0 UPDATE @ModifiedRawData
SET [RowLog Contents 0] = CAST('' AS XML).value('xs:hexBinary(substring(sql:column("[RowLog Contents 0_var]"),0))',
'varbinary(Max)')
FROM @ModifiedRawData
WHERE [LINK ID] = 0 UPDATE B
SET B.[RowLog Contents 0] = ( CASE WHEN A.[RowLog Contents 0] IS NOT NULL
AND C.[RowLog Contents 0] IS NOT NULL
THEN A.[RowLog Contents 0]
+ C.[RowLog Contents 0]
WHEN A.[RowLog Contents 0] IS NULL
AND C.[RowLog Contents 0] IS NOT NULL
THEN C.[RowLog Contents 0]
WHEN A.[RowLog Contents 0] IS NOT NULL
AND C.[RowLog Contents 0] IS NULL
THEN A.[RowLog Contents 0]
END ) ,
B.[Update] = ISNULL(B.[Update], 0) + 1
FROM @ModifiedRawData B
LEFT JOIN @ModifiedRawData A ON A.[Page IDS] = CONVERT(INT, CONVERT(VARBINARY(MAX), REVERSE(SUBSTRING(B.[RowLog Contents 0],
15 + 14, 2))))
AND A.[File IDS] = CONVERT(INT, CONVERT(VARBINARY(MAX), REVERSE(SUBSTRING(B.[RowLog Contents 0],
19 + 14, 2))))
AND A.[Link ID] = B.[Link ID]
LEFT JOIN @ModifiedRawData C ON C.[Page IDS] = CONVERT(INT, CONVERT(VARBINARY(MAX), REVERSE(SUBSTRING(B.[RowLog Contents 0],
27 + 14, 2))))
AND C.[File IDS] = CONVERT(INT, CONVERT(VARBINARY(MAX), REVERSE(SUBSTRING(B.[RowLog Contents 0],
31 + 14, 2))))
AND C.[Link ID] = B.[Link ID]
WHERE ( A.[RowLog Contents 0] IS NOT NULL
OR C.[RowLog Contents 0] IS NOT NULL
) UPDATE B
SET B.[RowLog Contents 0] = ( CASE WHEN A.[RowLog Contents 0] IS NOT NULL
AND C.[RowLog Contents 0] IS NOT NULL
THEN A.[RowLog Contents 0]
+ C.[RowLog Contents 0]
WHEN A.[RowLog Contents 0] IS NULL
AND C.[RowLog Contents 0] IS NOT NULL
THEN C.[RowLog Contents 0]
WHEN A.[RowLog Contents 0] IS NOT NULL
AND C.[RowLog Contents 0] IS NULL
THEN A.[RowLog Contents 0]
END )
--,B.[Update]=ISNULL(B.[Update],0)+1
FROM @ModifiedRawData B
LEFT JOIN @ModifiedRawData A ON A.[Page IDS] = CONVERT(INT, CONVERT(VARBINARY(MAX), REVERSE(SUBSTRING(B.[RowLog Contents 0],
15 + 14, 2))))
AND A.[File IDS] = CONVERT(INT, CONVERT(VARBINARY(MAX), REVERSE(SUBSTRING(B.[RowLog Contents 0],
19 + 14, 2))))
AND A.[Link ID] <> B.[Link ID]
AND B.[Update] = 0
LEFT JOIN @ModifiedRawData C ON C.[Page IDS] = CONVERT(INT, CONVERT(VARBINARY(MAX), REVERSE(SUBSTRING(B.[RowLog Contents 0],
27 + 14, 2))))
AND C.[File IDS] = CONVERT(INT, CONVERT(VARBINARY(MAX), REVERSE(SUBSTRING(B.[RowLog Contents 0],
31 + 14, 2))))
AND C.[Link ID] <> B.[Link ID]
AND B.[Update] = 0
WHERE ( A.[RowLog Contents 0] IS NOT NULL
OR C.[RowLog Contents 0] IS NOT NULL
) UPDATE @ModifiedRawData
SET [RowLog Contents 0] = ( CASE WHEN [RowLog Len] >= 8000
THEN SUBSTRING([RowLog Contents 0],
15, [RowLog Len])
WHEN [RowLog Len] < 8000
THEN SUBSTRING([RowLog Contents 0],
15 + 6,
CONVERT(INT, CONVERT(VARBINARY(MAX), REVERSE(SUBSTRING([RowLog Contents 0],
15, 6)))))
END )
FROM @ModifiedRawData
WHERE [LINK ID] = 0 UPDATE @ColumnNameAndData
SET [hex_Value] = [RowLog Contents 0]
--,A.[Update]=A.[Update]+1
FROM @ColumnNameAndData A
INNER JOIN @ModifiedRawData B ON CONVERT(INT, CONVERT(VARBINARY(MAX), REVERSE(SUBSTRING([hex_value],
17, 4)))) = [PAGE IDS]
AND CONVERT(INT, SUBSTRING([hex_value],
9, 2)) = B.[Link ID]
WHERE [System_Type_Id] IN ( 99, 167, 175, 231, 239, 241, 165, 98 )
AND [Link ID] <> 0 UPDATE @ColumnNameAndData
SET [hex_Value] = ( CASE WHEN B.[RowLog Contents 0] IS NOT NULL
AND C.[RowLog Contents 0] IS NOT NULL
THEN B.[RowLog Contents 0]
+ C.[RowLog Contents 0]
WHEN B.[RowLog Contents 0] IS NULL
AND C.[RowLog Contents 0] IS NOT NULL
THEN C.[RowLog Contents 0]
WHEN B.[RowLog Contents 0] IS NOT NULL
AND C.[RowLog Contents 0] IS NULL
THEN B.[RowLog Contents 0]
END )
--,A.[Update]=A.[Update]+1
FROM @ColumnNameAndData A
LEFT JOIN @ModifiedRawData B ON CONVERT(INT, CONVERT(VARBINARY(MAX), REVERSE(SUBSTRING([hex_value],
5, 4)))) = B.[PAGE IDS]
AND B.[Link ID] = 0
LEFT JOIN @ModifiedRawData C ON CONVERT(INT, CONVERT(VARBINARY(MAX), REVERSE(SUBSTRING([hex_value],
17, 4)))) = C.[PAGE IDS]
AND C.[Link ID] = 0
WHERE [System_Type_Id] IN ( 99, 167, 175, 231, 239, 241, 165, 98 )
AND ( B.[RowLog Contents 0] IS NOT NULL
OR C.[RowLog Contents 0] IS NOT NULL
) UPDATE @ColumnNameAndData
SET [hex_Value] = [RowLog Contents 0]
--,A.[Update]=A.[Update]+1
FROM @ColumnNameAndData A
INNER JOIN @ModifiedRawData B ON CONVERT(INT, CONVERT(VARBINARY(MAX), REVERSE(SUBSTRING([hex_value],
9, 4)))) = [PAGE IDS]
AND CONVERT(INT, SUBSTRING([hex_value],
3, 2)) = [Link ID]
WHERE [System_Type_Id] IN ( 35, 34, 99 )
AND [Link ID] <> 0 UPDATE @ColumnNameAndData
SET [hex_Value] = [RowLog Contents 0]
--,A.[Update]=A.[Update]+10
FROM @ColumnNameAndData A
INNER JOIN @ModifiedRawData B ON CONVERT(INT, CONVERT(VARBINARY(MAX), REVERSE(SUBSTRING([hex_value],
9, 4)))) = [PAGE IDS]
WHERE [System_Type_Id] IN ( 35, 34, 99 )
AND [Link ID] = 0 UPDATE @ColumnNameAndData
SET [hex_Value] = [RowLog Contents 0]
--,A.[Update]=A.[Update]+1
FROM @ColumnNameAndData A
INNER JOIN @ModifiedRawData B ON CONVERT(INT, CONVERT(VARBINARY(MAX), REVERSE(SUBSTRING([hex_value],
15, 4)))) = [PAGE IDS]
WHERE [System_Type_Id] IN ( 35, 34, 99 )
AND [Link ID] = 0 UPDATE @ColumnNameAndData
SET [hex_value] = 0xFFFE + SUBSTRING([hex_value], 9, LEN([hex_value]))
--,[Update]=[Update]+1
WHERE [system_type_id] = 241 CREATE TABLE [#temp_Data]
(
[FieldName] VARCHAR(MAX) ,
[FieldValue] NVARCHAR(MAX) ,
[Rowlogcontents] VARBINARY(8000) ,
[Row ID] INT
) INSERT INTO #temp_Data
SELECT NAME ,
CASE WHEN system_type_id IN ( 231, 239 )
THEN LTRIM(RTRIM(CONVERT(NVARCHAR(MAX), hex_Value))) --NVARCHAR ,NCHAR
WHEN system_type_id IN ( 167, 175 )
THEN LTRIM(RTRIM(CONVERT(VARCHAR(MAX), hex_Value))) --VARCHAR,CHAR
WHEN system_type_id IN ( 35 )
THEN LTRIM(RTRIM(CONVERT(VARCHAR(MAX), hex_Value))) --Text
WHEN system_type_id IN ( 99 )
THEN LTRIM(RTRIM(CONVERT(NVARCHAR(MAX), hex_Value))) --nText
WHEN system_type_id = 48
THEN CONVERT(VARCHAR(MAX), CONVERT(TINYINT, CONVERT(BINARY(1), REVERSE(hex_Value)))) --TINY INTEGER
WHEN system_type_id = 52
THEN CONVERT(VARCHAR(MAX), CONVERT(SMALLINT, CONVERT(BINARY(2), REVERSE(hex_Value)))) --SMALL INTEGER
WHEN system_type_id = 56
THEN CONVERT(VARCHAR(MAX), CONVERT(INT, CONVERT(BINARY(4), REVERSE(hex_Value)))) -- INTEGER
WHEN system_type_id = 127
THEN CONVERT(VARCHAR(MAX), CONVERT(BIGINT, CONVERT(BINARY(8), REVERSE(hex_Value))))-- BIG INTEGER
WHEN system_type_id = 61
THEN CONVERT(VARCHAR(MAX), CONVERT(DATETIME, CONVERT(VARBINARY(8000), REVERSE(hex_Value))), 100) --DATETIME
WHEN system_type_id = 58
THEN CONVERT(VARCHAR(MAX), CONVERT(SMALLDATETIME, CONVERT(VARBINARY(8000), REVERSE(hex_Value))), 100) --SMALL DATETIME
WHEN system_type_id = 108
THEN CONVERT(VARCHAR(MAX), CONVERT(NUMERIC(38, 20), CONVERT(VARBINARY, CONVERT(VARBINARY(1), xprec)
+ CONVERT(VARBINARY(1), xscale))
+ CONVERT(VARBINARY(1), 0) + hex_Value)) --- NUMERIC
WHEN system_type_id = 106
THEN CONVERT(VARCHAR(MAX), CONVERT(DECIMAL(38, 20), CONVERT(VARBINARY, CONVERT(VARBINARY(1), xprec)
+ CONVERT(VARBINARY(1), xscale))
+ CONVERT(VARBINARY(1), 0) + hex_Value)) --- DECIMAL
WHEN system_type_id IN ( 60, 122 )
THEN CONVERT(VARCHAR(MAX), CONVERT(MONEY, CONVERT(VARBINARY(8000), REVERSE(hex_Value))), 2) --MONEY,SMALLMONEY
WHEN system_type_id = 104
THEN CONVERT(VARCHAR(MAX), CONVERT (BIT, CONVERT(BINARY(1), hex_Value)
% 2)) -- BIT
WHEN system_type_id = 62
THEN RTRIM(LTRIM(STR(CONVERT(FLOAT, SIGN(CAST(CONVERT(VARBINARY(8000), REVERSE(hex_Value)) AS BIGINT))
* ( 1.0
+ ( CAST(CONVERT(VARBINARY(8000), REVERSE(hex_Value)) AS BIGINT)
& 0x000FFFFFFFFFFFFF )
* POWER(CAST(2 AS FLOAT),
-52) )
* POWER(CAST(2 AS FLOAT),
( ( CAST(CONVERT(VARBINARY(8000), REVERSE(hex_Value)) AS BIGINT)
& 0x7ff0000000000000 )
/ EXP(52 * LOG(2))
- 1023 ))), 53,
LEN(hex_Value)))) --- FLOAT
WHEN system_type_id = 59
THEN LEFT(LTRIM(STR(CAST(SIGN(CAST(CONVERT(VARBINARY(8000), REVERSE(hex_Value)) AS BIGINT))
* ( 1.0
+ ( CAST(CONVERT(VARBINARY(8000), REVERSE(hex_Value)) AS BIGINT)
& 0x007FFFFF )
* POWER(CAST(2 AS REAL), -23) )
* POWER(CAST(2 AS REAL),
( ( ( CAST(CONVERT(VARBINARY(8000), REVERSE(hex_Value)) AS INT) )
& 0x7f800000 )
/ EXP(23 * LOG(2))
- 127 )) AS REAL), 23,
23)), 8) --Real
WHEN system_type_id IN ( 165, 173 )
THEN ( CASE WHEN CHARINDEX(0x,
CAST('' AS XML).value('xs:hexBinary(sql:column("hex_Value"))',
'VARBINARY(8000)')) = 0
THEN '0x'
ELSE ''
END ) + CAST('' AS XML).value('xs:hexBinary(sql:column("hex_Value"))',
'varchar(max)') -- BINARY,VARBINARY
WHEN system_type_id = 34
THEN ( CASE WHEN CHARINDEX(0x,
CAST('' AS XML).value('xs:hexBinary(sql:column("hex_Value"))',
'VARBINARY(8000)')) = 0
THEN '0x'
ELSE ''
END ) + CAST('' AS XML).value('xs:hexBinary(sql:column("hex_Value"))',
'varchar(max)') --IMAGE
WHEN system_type_id = 36
THEN CONVERT(VARCHAR(MAX), CONVERT(UNIQUEIDENTIFIER, hex_Value)) --UNIQUEIDENTIFIER
WHEN system_type_id = 231
THEN CONVERT(VARCHAR(MAX), CONVERT(SYSNAME, hex_Value)) --SYSNAME
WHEN system_type_id = 241
THEN CONVERT(VARCHAR(MAX), CONVERT(XML, hex_Value)) --XML
WHEN system_type_id = 189
THEN ( CASE WHEN CHARINDEX(0x,
CAST('' AS XML).value('xs:hexBinary(sql:column("hex_Value"))',
'VARBINARY(8000)')) = 0
THEN '0x'
ELSE ''
END ) + CAST('' AS XML).value('xs:hexBinary(sql:column("hex_Value"))',
'varchar(max)') --TIMESTAMP
WHEN system_type_id = 98
THEN ( CASE WHEN CONVERT(INT, SUBSTRING(hex_Value, 1,
1)) = 56
THEN CONVERT(VARCHAR(MAX), CONVERT(INT, CONVERT(BINARY(4), REVERSE(SUBSTRING(hex_Value,
3,
LEN(hex_Value)))))) -- INTEGER
WHEN CONVERT(INT, SUBSTRING(hex_Value, 1,
1)) = 108
THEN CONVERT(VARCHAR(MAX), CONVERT(NUMERIC(38,
20), CONVERT(VARBINARY(1), SUBSTRING(hex_Value,
3, 1))
+ CONVERT(VARBINARY(1), SUBSTRING(hex_Value,
4, 1))
+ CONVERT(VARBINARY(1), 0)
+ SUBSTRING(hex_Value, 5,
LEN(hex_Value)))) --- NUMERIC
WHEN CONVERT(INT, SUBSTRING(hex_Value, 1,
1)) = 167
THEN LTRIM(RTRIM(CONVERT(VARCHAR(MAX), SUBSTRING(hex_Value,
9,
LEN(hex_Value))))) --VARCHAR,CHAR
WHEN CONVERT(INT, SUBSTRING(hex_Value, 1,
1)) = 36
THEN CONVERT(VARCHAR(MAX), CONVERT(UNIQUEIDENTIFIER, SUBSTRING(( hex_Value ),
3, 20))) --UNIQUEIDENTIFIER
WHEN CONVERT(INT, SUBSTRING(hex_Value, 1,
1)) = 61
THEN CONVERT(VARCHAR(MAX), CONVERT(DATETIME, CONVERT(VARBINARY(8000), REVERSE(SUBSTRING(hex_Value,
3,
LEN(hex_Value))))), 100) --DATETIME
WHEN CONVERT(INT, SUBSTRING(hex_Value, 1,
1)) = 165
THEN '0x'
+ SUBSTRING(( CASE WHEN CHARINDEX(0x,
CAST('' AS XML).value('xs:hexBinary(sql:column("hex_Value"))',
'VARBINARY(8000)')) = 0
THEN '0x'
ELSE ''
END )
+ CAST('' AS XML).value('xs:hexBinary(sql:column("hex_Value"))',
'varchar(max)'),
11, LEN(hex_Value)) -- BINARY,VARBINARY
END )
END AS FieldValue ,
[Rowlogcontents] ,
[Row ID]
FROM @ColumnNameAndData
ORDER BY nullbit --Create the column name in the same order to do pivot table. DECLARE @FieldName VARCHAR(MAX)
SET @FieldName = STUFF(( SELECT ','
+ CAST(QUOTENAME([Name]) AS VARCHAR(MAX))
FROM syscolumns
WHERE id = OBJECT_ID(''
+ @SchemaName_n_TableName
+ '')
FOR
XML PATH('')
), 1, 1, '') --Finally did pivot table and get the data back in the same format. SET @sql = 'SELECT ' + @FieldName
+ ' FROM #temp_Data PIVOT (Min([FieldValue]) FOR FieldName IN ('
+ @FieldName + ')) AS pvt'
EXEC sp_executesql @sql GO

恢复你的数据

--恢复数据,不加时间段条件  参数:数据库名,表名
--EXAMPLE #1 : FOR ALL DELETED RECORDS
EXEC Recover_Deleted_Data_Proc 'test','dbo.aa'
GO --恢复数据,加时间段条件
--EXAMPLE #2 : FOR ANY SPECIFIC DATE RANGE
EXEC Recover_Deleted_Data_Proc 'test','dbo.aa','2014-04-23','2014-04-23'

执行了下面的存储过程之后你会发现会显示出刚才删除的数据

EXEC Recover_Deleted_Data_Proc 'test','dbo.aa'
GO

恢复SQL Server被误删除的数据


解释

究竟他是如何工作的?让我们来一步一步来,这个过程涉及到7个步骤:

步骤1:

我们需要获得SQLSERVER删除的数据记录.使用标准SQLSERVER函数fn_dblog,我们能够容易的获得事务日志记录(包括

已删的数据。不过,我们只需要事务日志中选中的被删数据,所以我们的过滤条件需要包含3个字段 Context, Operation & AllocUnitName)

We need to get the deleted records from sql server. By using the standard SQL Server function fn_blog, we can easily get all transaction log (Including deleted data. But, we need only the selected deleted records from the transaction log. So we included three filters (Context, Operation , AllocUnitName).

  • Context (‘LCX_MARK_AS_GHOST’and ‘LCX_HEAP’)
  • Operation (‘LOP_DELETE_ROWS’)
  • AllocUnitName(‘dbo.aa’) –- Schema + table Name

Context可以说明是堆表还是聚集表

Operation:删除操作

AllocUnitName:分配单元名称,表名

下面是一个代码片段

SELECT  [RowLog Contents 0]
FROM sys.fn_dblog(NULL, NULL)
WHERE AllocUnitName = 'dbo.aa'
AND Context IN ( 'LCX_MARK_AS_GHOST', 'LCX_HEAP' )
AND Operation IN ( 'LOP_DELETE_ROWS' )

这个查询会返回不同列的信息,但是我们只需要选择[RowLog Contents 0]列,去获得被删除的数据的内容

RowLog content 0列的内容类似于这样

“0x300018000100000000000000006B0000564920205900000

00500E001002800426F62206A65727279″

步骤2:

现在,我们已经删除了数据,这些数据以hex码的形式放在事务日志里,这些hex码是有规律的,我们根据这些规律可以很容易恢复这些数据。

不过在恢复这些数据之前,我们需要理解这些格式。这些格式在KalenDelaney’s SQL Internal’s book.的书里面有讲解

  • 1 Byte : Status Bit A
  • 1 Byte : Status Bit B
  • 2 Bytes : Fixed length size
  • n Bytes : Fixed length data
  • 2 Bytes : Total Number of Columns
  • n Bytes : NULL Bitmap (1 bit for each column as 1 indicates that the column is null and 0 indicate that the column is not null)
  • 2 Bytes : Number of variable-length columns
  • n Bytes : Column offset array (2x variable length column)
  • n Bytes : Data for variable length columns

所以, hex码的“RowLog content 0″列的内容就等价于

“Status Bit A +Status Bit B +Fixed length size +Fixed length data +Total Number of Columns +NULL Bitmap +Number of variable-length columns +NULL Bitmap+Number of variable-length columns +Column offset array +Data for variable length columns.”

更详细的可以参考:SQL Server2008存储结构之堆表、行溢出

关于数据行的结构我们还可以采用稍微宏观一些的视角来查看。

恢复SQL Server被误删除的数据

  恢复SQL Server被误删除的数据

步骤3:

现在,我们需要解剖RowLog Content o列的内容(我们删除的数据的Hex码),利用上面的数据行的结构

  • [Fixed Length Data] = Substring (RowLog content 0, Status Bit A+Status Bit B + 1,2 bytes)
  • [Total No of Columns]= Substring (RowLog content 0, [Fixed Length Data] + 1,2 bytes)
  • [Null Bitmap length] = Ceiling ([Total No of Columns]/8.0)
  • [Null Bytes]= Substring (RowLog content 0, Status Bit A+ Status Bit B +[Fixed Length Data] +1, [Null Bitmap length] )
  • Total no of variable columns = Substring (RowLog content 0, Status Bit A+ Status Bit B + [Fixed Length Data] +1, [Null Bitmap length] + 2 )
  • Column Offset Array= Substring (RowLog content 0, Status Bit A+ Status Bit B + [Fixed Length Data] +1, [Null Bitmap length] + 2 , Total no of variable columns*2 )
  • Variable Column Start = Status Bit A+ Status Bit B + [Fixed Length Data] + [Null Bitmap length] + 2+( Total no of variable columns*2)

恢复SQL Server被误删除的数据

步骤4:

现在我们已经将hex码切开了(0x300008000100000002000001001300604F7D59),所以,我们能找到删除的行的某列的数据是否为null值

根据NULL位图。为了完成将NULL Bytes的hex码转换为二进制格式(正如之前讨论的,1表示行中对应的那一列为null,而0则表示对应的列有实际的数据)

如果还不是明白的童鞋可以看一下我写的这篇文章:《SQLSERVER中NULL位图的作用

恢复SQL Server被误删除的数据

步骤5:

现在,我们已经做了初步的数据分割 (Step-3) 和null值判断(Step-4) 。然后我们需要使用代码片段去获得列数据,例如:列名,列大小,精度,范围

和最重要的叶子的null位(确保列数据是固定长度的(<=-1表示可变长度)或者固定长度的(>=1))

使用下面的SQL语句

SELECT  *
FROM sys.allocation_units allocunits
INNER JOIN sys.partitions partitions ON ( allocunits.type IN ( 1, 3 )
AND partitions.hobt_id = allocunits.container_id
)
OR ( allocunits.type = 2
AND partitions.partition_id = allocunits.container_id
)
INNER JOIN sys.system_internals_partition_columns cols ON cols.partition_id = partitions.partition_id
LEFT OUTER JOIN syscolumns ON syscolumns.id = partitions.object_id
AND syscolumns.colid = cols.partition_column_id

与(Step-1,2,3,4) 获得的数据表做join连接,根据allocunits.[Allocation_Unit_Id]。

现在我们知道表和表中的数据信息,那么我们需要利用这些数据去将 [RowLog Contents 0] 列里的hex码的数据插入到表中的相应列

现在我们需要关心每一列的数据究竟是固定长度的还是可变长度的

恢复SQL Server被误删除的数据

步骤6:

我们收集了每列的hex格式的数据。现在我们需要利用[System_type_id]去转换这些数据回去正确的数据类型

每一种数据类型都有不同的数据类型转换机制。

--NVARCHAR ,NCHAR
WHEN system_type_id IN (231, 239) THEN LTRIM(RTRIM(CONVERT(NVARCHAR(max),hex_Value))) --VARCHAR,CHAR
WHEN system_type_id IN (167,175) THEN LTRIM(RTRIM(CONVERT(VARCHAR(max),REPLACE(hex_Value, 0x00, 0x20)))) --TINY INTEGER
WHEN system_type_id = 48 THEN CONVERT(VARCHAR(MAX), CONVERT(TINYINT, CONVERT(BINARY(1), REVERSE (hex_Value)))) --SMALL INTEGER
WHEN system_type_id = 52 THEN CONVERT(VARCHAR(MAX), CONVERT(SMALLINT, CONVERT(BINARY(2), REVERSE (hex_Value)))) -- INTEGER
WHEN system_type_id = 56 THEN CONVERT(VARCHAR(MAX), CONVERT(INT, CONVERT(BINARY(4), REVERSE(hex_Value)))) -- BIG INTEGER
WHEN system_type_id = 127 THEN CONVERT(VARCHAR(MAX), CONVERT(BIGINT, CONVERT(BINARY(8), REVERSE(hex_Value)))) --DATETIME
WHEN system_type_id = 61 Then CONVERT(VARCHAR(Max),CONVERT(DATETIME,Convert(VARBINARY(max),REVERSE (hex_Value))),100) --SMALL DATETIME
WHEN system_type_id =58 Then CONVERT(VARCHAR(Max),CONVERT(SMALLDATETIME,CONVERT(VARBINARY(MAX),REVERSE(hex_Value))),100) --SMALL DATETIME --- NUMERIC
WHEN system_type_id = 108 THEN CONVERT(VARCHAR(MAX), CAST(CONVERT(NUMERIC(18,14), CONVERT(VARBINARY,CONVERT(VARBINARY,xprec)+CONVERT(VARBINARY,xscale))+CONVERT(VARBINARY(1),0) + hex_Value) as FLOAT)) --MONEY,SMALLMONEY
WHEN system_type_id In(60,122) THEN CONVERT(VARCHAR(MAX),Convert(MONEY,Convert(VARBINARY(MAX),Reverse(hex_Value))),2) --- DECIMAL
WHEN system_type_id = 106 THEN CONVERT(VARCHAR(MAX), CAST(CONVERT(Decimal(38,34), Convert(VARBINARY,Convert(VARBINARY,xprec)+CONVERT(VARBINARY,xscale))+CONVERT(VARBINARY(1),0) + hex_Value) as FLOAT)) -- BIT
WHEN system_type_id = 104 THEN CONVERT(VARCHAR(MAX),CONVERT (BIT,CONVERT(BINARY(1), hex_Value)%2)) --- FLOAT
WHEN system_type_id = 62 THEN RTRIM(LTRIM(Str(Convert(FLOAT,SIGN(CAST(Convert(VARBINARY(max),Reverse(hex_Value)) AS BIGINT)) * (1.0 + (CAST(CONVERT(VARBINARY(max),Reverse(hex_Value)) AS BIGINT) & 0x000FFFFFFFFFFFFF) * POWER(CAST(2 AS FLOAT), -52)) * POWER(CAST(2 AS FLOAT),((CAST(CONVERT(VARBINARY(max),Reverse(hex_Value)) AS BIGINT) & 0x7ff0000000000000) / EXP(52 * LOG(2))-1023))),53,LEN(hex_Value)))) --REAL
When system_type_id =59 THEN Left(LTRIM(STR(Cast(SIGN(CAST(Convert(VARBINARY(max),Reverse(hex_Value)) AS BIGINT))* (1.0 + (CAST(CONVERT(VARBINARY(max),Reverse(hex_Value)) AS BIGINT) & 0x007FFFFF) * POWER(CAST(2 AS Real), -23)) * POWER(CAST(2 AS Real),(((CAST(CONVERT(VARBINARY(max),Reverse(hex_Value)) AS INT) )& 0x7f800000)/ EXP(23 * LOG(2))-127))AS REAL),23,23)),8) --BINARY,VARBINARY
WHEN system_type_id In (165,173) THEN (CASE WHEN Charindex(0x,cast('' AS XML).value('xs:hexBinary(sql:column("hex_value"))', 'varbinary(max)')) = 0 THEN '0x' ELSE '' END) +cast('' AS XML).value('xs:hexBinary(sql:column("hex_value"))', 'varchar(max)') --UNIQUEIDENTIFIER
WHEN system_type_id =36 THEN CONVERT(VARCHAR(MAX),CONVERT(UNIQUEIDENTIFIER,hex_Value))

恢复SQL Server被误删除的数据

步骤7:

最终我们做一个数据透视表,你会看到最后的结果:被删的数据回来了!

注意:这些数据只是展示出来并没有自动插入回表中,你需要将这些数据重新插入回去表中!

恢复SQL Server被误删除的数据


我的测试

经过测试,作者写的这个存储过程还是有些问题

如果你创建的测试表的数据类型有xml或者是一些text数据类型的字段会有报错

Msg 537, Level 16, State 3, Procedure Recover_Deleted_Data_Proc, Line 525
Invalid length parameter passed to the LEFT or SUBSTRING function. Msg 9420, Level 16, State 1, Procedure Recover_Deleted_Data_Proc, Line 651
XML parsing: line 1, character 2, illegal xml character

但是一般的数据类型则不会,例如nvarchar这些

还有不要在存储过程的最后加

--Recover the deleted data without date range
EXEC Recover_Deleted_Data_Proc 'test','dbo.Test_Table'
GO
--Recover the deleted data it with date range
EXEC Recover_Deleted_Data_Proc 'test','dbo.Test_Table','2012-06-01','2012-06-30'

否则会报错

消息 50000,级别 16,状态 1,过程 Recover_Deleted_Data_Proc,第 290 行
There is no data in the log as per the search criteria

总结

实际上这个存储过程还是挺有研究意义的,对于想做一个跟Log Explorer for SQL Server软件功能差不多的软件出来

还是有可能的,跟着作者的思路,一步一步实现

苦于最近太忙,先分享出来,以后再研究这个存储过程了~

如有不对的地方,欢迎大家拍砖o(∩_∩)o 

支持date类型 感谢园友 dwchaoyue

EXEC Recover_Deleted_Data_Proc 'sss','dbo.testdaterecover','2014-04-23','2014-10-23'
--DROP TABLE testdaterecover
CREATE TABLE testdaterecover(dd DATE,cc DATETIME)
GO
INSERT INTO [dbo].[testdaterecover]
( [dd], [cc] )
VALUES ( GETDATE(), -- dd - date
GETDATE() -- cc - datetime
) SELECT CONVERT(VARCHAR(MAX),CONVERT(DATETIME, CONVERT(VARBINARY(8000),[cc])),120) FROM [dbo].[testdaterecover] DELETE [dbo].[testdaterecover] THEN CONVERT(VARCHAR(MAX), CONVERT(DATETIME, CONVERT(VARBINARY(8000), REVERSE(hex_Value))), 121) --DATETIME

2015-12-17 补充

注意:脚本中大量使用了reverse函数来进行转换,因为reverse函数的定义是返回字符串值的逆序,不是字节的逆序

那么就会导致有些数据类型是按字节逆序的,就会出错

恢复SQL Server被误删除的数据

WHEN system_type_id = 52 THEN CONVERT(VARCHAR(MAX), CONVERT(SMALLINT, CONVERT(BINARY(2), REVERSE (hex_Value))))

在SQL Server中,sys.fn_PhysLocFormatter这个函数也是使用reverse函数进行RID逆序,当遇到81-FE之间的字节时 被认为是双字节字符组合在一起参与逆序运算

所以得出来的某些结果也是错的,详细请参考《SQL Server性能调优实战》 P115

函数的逻辑是,每个字节加上相应的位数

比如 2这个数字是在第二个字节位置的,那么公式就是2*POWER(2,8) =512

相应进制

二进制后面加8个0

十六进制后面加2个0

恢复SQL Server被误删除的数据

恢复SQL Server被误删除的数据

恢复SQL Server被误删除的数据

恢复SQL Server被误删除的数据

只要学过计算机基础都不难理解的

本文版权归作者所有,未经作者同意不得转载。