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access下如何恢復已經刪除的記錄;如何恢復已經刪除的表、窗體等

時間:2008-11-22 23:27 來源:未知 作者:dxy 閱讀:

問題:
如何恢復已經刪除的記錄;如何恢復已經刪除的表、窗體等等對象
1、我用 DELETE FROM TABLE 刪除了一些記錄,現在發現誤刪除了,該如何恢復?
2、我直接手動刪除或者用 DROP TABLE 刪除了一個表,現在發現是誤刪除了,該如何恢復?
3、我手動刪除了一個窗體,該如何恢復?
4、我刪除了記錄,可是數據庫體積并沒有減小,那么是否能找回記錄呢?


回答:
1、已經刪除的記錄是無法恢復的,ACCESS 不是 FOXPRO,MDB 格式不是 DBF 格式,沒有邏輯刪除和物理刪除的概念,一旦刪除就無法恢復了。
2、無法恢復,但是你可以查看一下,有沒有隱藏的以 "~" 符號開頭的表,更改該表的名稱有可能找回你需要的表。
3、無法恢復,但是你可以查看一下有沒有系統隱藏的對象,有時候對象被刪除時系統并不直接刪除,而是更改對象名后隱藏它。
4、數據庫體積的確沒有變小,你壓縮修復數據庫后體積就會變小了。那是因為在二進制上你的數據的確沒有被刪除,仍然存放在磁盤的某個扇區,但是微軟沒有提供 MDB 格式二進制組織方式的參考資料(微軟也不會提供,其他第三方公司也沒有權利直接反編譯 MDB 格式)。至今為止,中國大陸我也沒有看到過相關的參考資料。所以目前為止,你已經刪除的數據是無法恢復的。但是你可以嘗試使用磁盤恢復軟件來找到恢復數據的方法,但是該方法不在本文討論范圍。
建議:在建立數據庫結構時,可以在各個表中再多加一個 ISDEL 字段,刪除記錄時不使用 DELETE FROM ,而使用 UPDATE TABLE SET ISDEL=TRUE 這樣的語句,然后在界面上不顯示 ISDEL=TRUE 的記錄即可。
[復制此代碼]CODE:
如果還沒有被壓縮理論上可以。試試這段代碼吧。加在access模組中
恢復刪除的工作表(未被壓縮)
 
Public Function FnUndeleteObjects() As Boolean
On Error GoTo ErrorHandler:
Dim strObjectName As String
Dim rsTables As DAO.Recordset
Dim dbsDatabase As DAO.Database
Dim tDef As DAO.TableDef
Dim qDef As DAO.QueryDef
Dim intNumDeletedItemsFound As Integer
Set dbsDatabase = CurrentDb
For Each tDef In dbsDatabase.TableDefs
'This is actually used as a 'Deleted Flag'
If tDef.Attributes And dbHiddenObject Then
strObjectName = FnGetDeletedTableNameByProp(tDef.Name)
strObjectName = InputBox("A deleted TABLE has been found." & _
vbCrLf & vbCrLf & _
"To undelete this object, enter a new name:", _
"Access Undelete Table", strObjectName)
If Len(strObjectName) > 0 Then
FnUndeleteTable CurrentDb, tDef.Name, strObjectName
End If
intNumDeletedItemsFound = intNumDeletedItemsFound + 1
End If
Next tDef
For Each qDef In dbsDatabase.QueryDefs
'Note 'Attributes' flag is not exposed for QueryDef objects,
'We could look up the flag by using MSysObjects but
'new queries don't get written to MSysObjects until
'Access is closed. Therefore we'll just check the
'start of the name is '~TMPCLP' ...
If InStr(1, qDef.Name, "~TMPCLP") = 1 Then
strObjectName = ""
strObjectName = InputBox("A deleted QUERY has been found." & _
vbCrLf & vbCrLf & _
"To undelete this object, enter a new name:", _
"Access Undelete Query", strObjectName)
If Len(strObjectName) > 0 Then
If FnUndeleteQuery(CurrentDb, qDef.Name, strObjectName) Then
'We'll rename the deleted object since we've made a
'copy and won't be needing to re-undelete it.
'(To break the condition "~TMPCLP" in future...)
qDef.Name = "~TMPCLQ" & Right$(qDef.Name, Len(qDef.Name) - 7)
End If
End If
intNumDeletedItemsFound = intNumDeletedItemsFound + 1
End If
Next qDef
If intNumDeletedItemsFound = 0 Then
MsgBox "Unable to find any deleted tables/queries to undelete!"
End If
Set dbsDatabase = Nothing
FnUndeleteObjects = True
ExitFunction:
Exit Function
ErrorHandler:
MsgBox "Error occured in FnUndeleteObjects() - " & _
Err.Description & " (" & CStr(Err.Number) & ")"
GoTo ExitFunction
End Function

Private Function FnUndeleteTable(dbDatabase As DAO.Database, _
strDeletedTableName As String, _
strNewTableName As String)
'Module (c) 2005 Wayne Phillips (http://www.everythingaccess.com)
'Written 18/04/2005
Dim tDef As DAO.TableDef
Set tDef = dbDatabase.TableDefs(strDeletedTableName)
'Remove the Deleted Flag...
tDef.Attributes = tDef.Attributes And Not dbHiddenObject
'Rename the deleted object to the original or new name...
tDef.Name = strNewTableName
dbDatabase.TableDefs.Refresh
Application.RefreshDatabaseWindow
Set tDef = Nothing
End Function
Private Function FnUndeleteQuery(dbDatabase As DAO.Database, _
strDeletedQueryName As String, _
strNewQueryName As String)
'Module (c) 2005 Wayne Phillips (http://www.everythingaccess.com)
'Written 18/04/2005
'We can't just remove the Deleted flag on queries
'('Attributes' is not an exposed property)
'So instead we create a new query with the SQL...
'Note: Can't use DoCmd.CopyObject as it copies the dbHiddenObject attribute!
If FnCopyQuery(dbDatabase, strDeletedQueryName, strNewQueryName) Then
FnUndeleteQuery = True
Application.RefreshDatabaseWindow
End If
End Function

Private Function FnCopyQuery(dbDatabase As DAO.Database, _
strSourceName As String, _
strDestinationName As String)
'Module (c) 2005 Wayne Phillips (http://www.everythingaccess.com)
'Written 18/04/2005
On Error GoTo ErrorHandler:
Dim qDefOld As DAO.QueryDef
Dim qDefNew As DAO.QueryDef
Dim Field As DAO.Field
Set qDefOld = dbDatabase.QueryDefs(strSourceName)
Set qDefNew = dbDatabase.CreateQueryDef(strDestinationName, qDefOld.SQL)
'Copy root query properties...
FnCopyLvProperties qDefNew, qDefOld.Properties, qDefNew.Properties
For Each Field In qDefOld.Fields
'Copy each fields individual properties...
FnCopyLvProperties qDefNew.Fields(Field.Name), _
Field.Properties, _
qDefNew.Fields(Field.Name).Properties
Next Field
dbDatabase.QueryDefs.Refresh
FnCopyQuery = True
ExitFunction:
Set qDefNew = Nothing
Set qDefOld = Nothing
Exit Function
ErrorHandler:
MsgBox "Error re-creating query '" & strDestinationName & "':" & vbCrLf & _
Err.Description & " (" & CStr(Err.Number) & ")"
GoTo ExitFunction
End Function
Private Function PropExists(Props As DAO.Properties, strPropName As String) As Boolean
'Module (c) 2005 Wayne Phillips (http://www.everythingaccess.com)
'Written 18/04/2005
'If properties fail to be created, we'll just ignore the errors
On Error Resume Next
Dim Prop As DAO.Property
For Each Prop In Props
If Prop.Name = strPropName Then
PropExists = True
Exit Function ' Short circuit
End If
Next Prop
PropExists = False
End Function
Private Sub FnCopyLvProperties(objObject As Object, OldProps As DAO.Properties, NewProps As DAO.Properties)
'Module (c) 2005 Wayne Phillips (http://www.everythingaccess.com)
'Written 18/04/2005
'If properties fail to be created, we'll just ignore the errors
On Error Resume Next
Dim Prop As DAO.Property
Dim NewProp As DAO.Property
For Each Prop In OldProps
If Not PropExists(NewProps, Prop.Name) Then
If IsNumeric(Prop.Value) Then
NewProps.Append objObject.CreateProperty(Prop.Name, Prop.Type, CLng(Prop.Value))
Else
NewProps.Append objObject.CreateProperty(Prop.Name, Prop.Type, Prop.Value)
End If
Else
With NewProps(Prop.Name)
.Type = Prop.Type
.Value = Prop.Value
End With
End If
Next Prop
End Sub
Private Function FnGetDeletedTableNameByProp(strRealTableName As String) As String
'Module (c) 2005 Wayne Phillips (http://www.everythingaccess.com)
'Written 18/04/2005
'If an error occurs here, just ignore (user will override the blank name)
On Error Resume Next
Dim i As Long
Dim strNameMap As String
'Look up the Unicode translation NameMap property to try to guess the
'original table name... (Access 2000+ only - and doesn't always exist?!)
strNameMap = CurrentDb.TableDefs(strRealTableName).Properties("NameMap")
strNameMap = Mid(strNameMap, 23) 'Offset of the table name...
'Find the null terminator...
i = 1
If Len(strNameMap) > 0 Then
While (i < Len(strNameMap)) And (Asc(Mid(strNameMap, i)) <> 0)
i = i + 1
Wend
End If
FnGetDeletedTableNameByProp = Left(strNameMap, i - 1)
End Function

 

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