This example uses the AppendChunk and GetChunk methods to fill an image field with data from another record, 32K at a time. In a real application, one might use a procedure like this to copy a record containing a photo or graphic image field from one table to another. In this example, the record is simply being copied back to same table. Note that all the chunk manipulation takes place within a single AddNew-Update sequence. Public Sub AppendChunkX() Dim cnn1 As ADODB.Connection
Dim rstPubInfo As ADODB.Recordset
Dim strCnn As String
Dim strPubID As String
Dim strPRInfo As String
Dim lngOffset As Long
Dim lngLogoSize As Long
Dim varLogo As Variant
Dim varChunk As Variant
Const conChunkSize = 100 ' Open a connection.
Set cnn1 = New ADODB.Connection
strCnn = "driver={SQL Server};server=srv;" & _
"uid=sa;pwd=;database=pubs"
cnn1.Open strCnn
' Open the pub_info table.
Set rstPubInfo = New ADODB.Recordset
rstPubInfo.CursorType = adOpenKeyset
rstPubInfo.LockType = adLockOptimistic
rstPubInfo.Open "pub_info", cnn1, , , adCmdTable
' Prompt for a logo to copy.
strMsg = "Available logos are : " & vbCr & vbCr
Do While Not rstPubInfo.EOF
strMsg = strMsg & rstPubInfo!pub_id & vbCr & _
Left(rstPubInfo!pr_info, InStr(rstPubInfo!pr_info, ",") - 1) & _
vbCr & vbCr
rstPubInfo.MoveNext
Loop
strMsg = strMsg & "Enter the ID of a logo to copy:"
strPubID = InputBox(strMsg)
' Copy the logo to a variable in chunks.
rstPubInfo.Filter = "pub_id = '" & strPubID & "'"
lngLogoSize = rstPubInfo!logo.ActualSize
Do While lngOffset < lngLogoSize
varChunk = rstPubInfo!logo.GetChunk(conChunkSize)
varLogo = varLogo & varChunk
lngOffset = lngOffset + conChunkSize
Loop
' Get data from the user.
strPubID = Trim(InputBox("Enter a new pub ID:"))
strPRInfo = Trim(InputBox("Enter descriptive text:"))
' Add a new record, copying the logo in chunks.
rstPubInfo.AddNew
rstPubInfo!pub_id = strPubID
rstPubInfo!pr_info = strPRInfo lngOffset = 0 ' Reset offset.
Do While lngOffset < lngLogoSize
varChunk = LeftB(RightB(varLogo, lngLogoSize - lngOffset), _
conChunkSize)
rstPubInfo!logo.AppendChunk varChunk
lngOffset = lngOffset + conChunkSize
Loop
rstPubInfo.Update
' Show the newly added data.
MsgBox "New record: " & rstPubInfo!pub_id & vbCr & _
"Description: " & rstPubInfo!pr_info & vbCr & _
"Logo size: " & rstPubInfo!logo.ActualSize ' Delete new record because this is a demonstration.
rstPubInfo.Requery
cnn1.Execute "DELETE FROM pub_info " & _
"WHERE pub_id = '" & strPubID & "'" rstPubInfo.Close
cnn1.Close End Sub
Dim rstPubInfo As ADODB.Recordset
Dim strCnn As String
Dim strPubID As String
Dim strPRInfo As String
Dim lngOffset As Long
Dim lngLogoSize As Long
Dim varLogo As Variant
Dim varChunk As Variant
Const conChunkSize = 100 ' Open a connection.
Set cnn1 = New ADODB.Connection
strCnn = "driver={SQL Server};server=srv;" & _
"uid=sa;pwd=;database=pubs"
cnn1.Open strCnn
' Open the pub_info table.
Set rstPubInfo = New ADODB.Recordset
rstPubInfo.CursorType = adOpenKeyset
rstPubInfo.LockType = adLockOptimistic
rstPubInfo.Open "pub_info", cnn1, , , adCmdTable
' Prompt for a logo to copy.
strMsg = "Available logos are : " & vbCr & vbCr
Do While Not rstPubInfo.EOF
strMsg = strMsg & rstPubInfo!pub_id & vbCr & _
Left(rstPubInfo!pr_info, InStr(rstPubInfo!pr_info, ",") - 1) & _
vbCr & vbCr
rstPubInfo.MoveNext
Loop
strMsg = strMsg & "Enter the ID of a logo to copy:"
strPubID = InputBox(strMsg)
' Copy the logo to a variable in chunks.
rstPubInfo.Filter = "pub_id = '" & strPubID & "'"
lngLogoSize = rstPubInfo!logo.ActualSize
Do While lngOffset < lngLogoSize
varChunk = rstPubInfo!logo.GetChunk(conChunkSize)
varLogo = varLogo & varChunk
lngOffset = lngOffset + conChunkSize
Loop
' Get data from the user.
strPubID = Trim(InputBox("Enter a new pub ID:"))
strPRInfo = Trim(InputBox("Enter descriptive text:"))
' Add a new record, copying the logo in chunks.
rstPubInfo.AddNew
rstPubInfo!pub_id = strPubID
rstPubInfo!pr_info = strPRInfo lngOffset = 0 ' Reset offset.
Do While lngOffset < lngLogoSize
varChunk = LeftB(RightB(varLogo, lngLogoSize - lngOffset), _
conChunkSize)
rstPubInfo!logo.AppendChunk varChunk
lngOffset = lngOffset + conChunkSize
Loop
rstPubInfo.Update
' Show the newly added data.
MsgBox "New record: " & rstPubInfo!pub_id & vbCr & _
"Description: " & rstPubInfo!pr_info & vbCr & _
"Logo size: " & rstPubInfo!logo.ActualSize ' Delete new record because this is a demonstration.
rstPubInfo.Requery
cnn1.Execute "DELETE FROM pub_info " & _
"WHERE pub_id = '" & strPubID & "'" rstPubInfo.Close
cnn1.Close End Sub
Dim rs As New ADODB.Recordset
Dim stm As ADODB.StreamPrivate Sub SavePictureToDB(cn As ADODB.Connection)
'将BMP图片存入数据库
On Error GoTo EH
Set stm = New ADODB.Stream
rs.Open "select ImagePath,ImageValue from tbl_Image", cn, adOpenKeyset, adLockOptimistic
CommonDialog1.ShowOpen
Text1.Text = CommonDialog1.FileName
With stm
.Type = adTypeBinary
.Open
.LoadFromFile CommonDialog1.FileName
End With
With rs
.AddNew
.Fields("ImagePath") = Text1.Text
.Fields("ImageValue") = stm.Read
.Update
End With
rs.Close
Set rs = Nothing
Exit Sub
EH: MsgBox Err.Description, vbInformation, "Error"
End Sub
Private Sub LoadPictureFromDB(cn As ADODB.Connection)
'载数据库中读出BMP图片
On Error GoTo EH
Dim strTemp As String
Set stm = New ADODB.Stream
strTemp = "c:\temp.tmp" '临时文件,用来保存读出的图片
rs.Open "select ImagePath,ImageValue from tbl_image", cn, , , adCmdText
With stm
.Type = adTypeBinary
.Open
.Write rs("ImageValue")
.SaveToFile strTemp, adSaveCreateOverWrite
.Close
End With
Image1.Picture = LoadPicture(strTemp)
Set stm = Nothing
rs.Close
Set rs = Nothing
Exit Sub
EH: MsgBox Err.Description, vbInformation, "Error"
End Sub
ptQuery->SQL->Clear();
ptQuery->SQL->Add( stSql ) ;ptQuery->Parameters->ParamByName( "content" )->LoadFromFile( OpenDialog1->FileName, ftBlob );ptQuery->ExecSQL() ;
ptQuery->SQL->Clear();
ptQuery->SQL->Add( stSql ) ;ptQuery->Parameters->ParamByName( "content" )->LoadFromFile( OpenDialog1->FileName, ftBlob );ptQuery->ExecSQL() ;
ptQuery->SQL->Clear();
ptQuery->SQL->Add( stSql ) ;ptQuery->Parameters->ParamByName( "content" )->LoadFromFile( OpenDialog1->FileName, ftBlob );ptQuery->ExecSQL() ;