でファイルを生成するSQL ServerのBLOB列にファイルを書き込むために:コードを読み込んで使用して別のバイト
- MS-SQL Serverの2014
- SQL へのリンクODBCテーブルとMSアクセス2013 Serverデータベース
- "SQL Serverの" ODBCドライバ(10.00.10586.00、マイクロソフト社 、SQLSRV32.DLL)
- DAO
SQL Serverのblob(varbinary [max])列にファイルをアップロードし、後でファイルをダウンロードするために、Accessアプリケーションのフォームの背後にあるVBAコードを使用して、SQL Server 2014データベースにリンクされたODBCテーブルを持つAccessデータベースがあります同じブロブ列から取得します。
しかし、blob列から先にアップロードされたファイルを取得すると、保存されたファイルにファイルの最後に追加のバイトが追加されることがわかりました。
向こうの比較で2つのファイルの比較の画面キャプチャは以下の通りです:誰かがチェックし、コード内の誤りを指摘することができれば、私は感謝
。コードは次のとおりです。
Function ReadBLOB(SourceFileName As String, TableName As String, FieldName As String, _
IDFieldName As String, IDFieldValue As Variant)
Dim NumBlocks As Integer, SourceFile As Integer, i As Integer
Dim FileLength As Long
Dim LeftOver As Long
Dim FileData() As Byte
Dim RetVal As Variant
Dim BlockSize As Long
Dim s As String
On Error GoTo Err_ReadBLOB
BlockSize = 32767
' Open the source file.
SourceFile = FreeFile
Open SourceFileName For Binary Access Read As SourceFile
' Get the length of the file.
FileLength = LOF(SourceFile)
If FileLength = 0 Then
ReadBLOB = 0
Exit Function
End If
' Calculate the number of blocks to read and leftover bytes.
NumBlocks = FileLength \ BlockSize
LeftOver = FileLength Mod BlockSize
Dim T As dao.Recordset
If TypeName(IDFieldValue) = "String" Then
IDFieldValue = "'" & IDFieldValue & "'"
End If
s = "SELECT [" & FieldName & "] FROM [" & TableName & "] WHERE [" & IDFieldName & "] = " & IDFieldValue
Set T = CurrentDb.OpenRecordset(s, dbOpenDynaset, dbSeeChanges)
T.Edit
' Read the 1st block of data (upto Leftover in size), writing it to the table.
'FileData = String$(LeftOver, 32)
ReDim FileData(LeftOver)
Get SourceFile, , FileData
T(FieldName).AppendChunk (FileData)
' Read the remaining blocks of data, writing them to the table.
'FileData = String$(BlockSize, 32)
ReDim FileData(BlockSize)
For i = 1 To NumBlocks
Get SourceFile, , FileData
T(FieldName).AppendChunk (FileData)
Next i
' Update the record and terminate function.
T.Update
Close SourceFile
ReadBLOB = FileLength
Exit Function
Err_ReadBLOB:
ReadBLOB = -Err
MsgBox Err.Description
Exit Function
End Function
Function WriteBLOB2(TableName As String, FieldName As String, IDFieldName As String, _
IDFieldValue As Variant, DestinationFileName As String) As Long
Dim NumBlocks As Integer, DestFile As Integer, i As Integer
Dim FileLength As Long, LeftOver As Long
Dim FileData() As Byte
Dim RetVal As Variant
Dim BlockSize As Long
Dim s As String
Dim f As String
On Error GoTo Err_WriteBLOB
BlockSize = 32767
Dim T As dao.Recordset
If TypeName(IDFieldValue) = "String" Then
IDFieldValue = "'" & IDFieldValue & "'"
End If
s = "SELECT [" & FieldName & "] FROM [" & TableName & "] WHERE [" & IDFieldName & "] = " & IDFieldValue
Set T = CurrentDb.OpenRecordset(s, dbOpenSnapshot, dbSeeChanges)
If T.RecordCount = 0 Then
WriteBLOB2 = 0
Exit Function
End If
' Get the size of the field.
FileLength = T(FieldName).FieldSize()
If FileLength = 0 Then
WriteBLOB2 = 0
Exit Function
End If
' Calculate number of blocks to write and leftover bytes.
NumBlocks = FileLength \ BlockSize
LeftOver = FileLength Mod BlockSize
' Remove any existing destination file.
DestFile = FreeFile
Open DestinationFileName For Output As DestFile
Close DestFile
' Open the destination file.
Open DestinationFileName For Binary As DestFile
' Write the leftover data to the output file.
FileData = T(FieldName).GetChunk(0, LeftOver)
Put DestFile, , FileData
' Write the remaining blocks of data to the output file.
For i = 1 To NumBlocks
' Reads a chunk and writes it to output file.
FileData = T(FieldName).GetChunk((i - 1) * BlockSize + LeftOver, BlockSize)
Put DestFile, , FileData
Next i
' Terminates function
Close DestFile
WriteBLOB2 = FileLength
Exit Function
Err_WriteBLOB:
WriteBLOB2 = -Err
MsgBox Err.Description
Exit Function
End Function
Public Sub ClearSQLBlob2(TableName As String, FieldName As String, _
IDFieldName As String, IDFieldValue As Variant)
If TypeName(IDFieldValue) = "String" Then
IDFieldValue = "'" & IDFieldValue & "'"
End If
DoCmd.SetWarnings False
DoCmd.RunSQL "UPDATE [" & TableName & "] SET [" & FieldName & "] = NULL WHERE [" & IDFieldName & "] = " & IDFieldValue
DoCmd.SetWarnings True
End Sub
あなたの質問から重要でないコード、特にそれらすべての 'SysCmd'呼び出しを削除すると助けになります。 – Andre
@Andre:Done .... –
BLOB列の値に元のデータが含まれていることを100%確信していますか?または、アップロード中にデータが既に破損していますか?最後に追加される値は何ですか? – erg