如何用VB+SQL保存,读取数据库中的图片

我这里有一个ACCESS的例子,你参考参考吧
Option Explicit
Dim b As ADODB.Recordset
Dim c As ADODB.Stream
Dim conn As New ADODB.ConnectionPrivate Sub Command1_Click()    conn.Open "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=D:\1.mdb;Persist Security Info=False"
    conn.Execute "create table a (Str longbinary)"
End SubPrivate Sub Command2_Click()
    Set b = New ADODB.Recordset
    Set c = New ADODB.Stream
    c.Mode = adModeReadWrite
    c.Type = adTypeBinary
    c.Open
    c.LoadFromFile "D:\ss.JPG"
    b.Open "select * from a", "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=D:\1.mdb;Persist Security Info=False", adOpenDynamic, adLockOptimistic
    b.AddNew
    b.Fields.Item(0).Value = c.Read()    b.Update
    b.Close
Set b = New ADODB.Recordset
    b.Open "select * from a", "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=D:1.mdb;Persist Security Info=False", adOpenKeyset, adLockOptimistic
    MsgBox b.RecordCount
    b.MoveLast
    c.Write (b.Fields.Item(0).Value)
    c.SaveToFile "d:\aa.JPG", adSaveCreateOverWrite
    Picture1.Picture = LoadPicture("D:\aa.JPG")
End Sub

转贴(摘自www.china-askpro.com)：
   注:写图片文件到数据库
    Col为栏位名,ImgFile为要写到数据库的图片文件名,BockSize为每次写多少字节,缺省为每次写8K字节到数据库
    Public Sub WriteDB(Col As ADODB.Field, ImgFile As String, Optional BlockSize As Long=8192)
     Dim byteData() As Byte, FileLength As Long, NumBlocks As Integer
     Dim LeftOver As Long, SourceFileNum As Integer, i As Integer

     SourceFileNum = FreeFile
     Open ImgFile For Binary As SourceFileNum
     FileLength = LOF(SourceFileNum)
     If FileLength > 50 Then
     NumBlocks = FileLength \ BlockSize
     LeftOver = FileLength Mod BlockSize

     ReDim byteData(LeftOver)
     Get SourceFileNum, , byteData()
     Col.AppendChunk byteData()
     ReDim byteData(BlockSize)
     For i = 1 To NumBlocks
     Get SourceFileNum, , byteData()
     Col.AppendChunk byteData()
     Next
     End If
     Close SourceFileNum
    End Sub


    ImgFile为从数据库读出数据写到磁盘的文件名,BlockSize为每次向文件写多少个字节,缺省为8K字节,当ReadDB=True,得到图片文件後,可以用LoadPicter(图片文件名)显示图片到PictureBox或Image框中.
    Public Function ReadDB(Col As ADODB.Field, ImgFile As String,Optional BlockSize As Long=8192) As Boolean
     Dim byteData() As Byte, NumBlocks As Integer
     Dim LeftOver As Long, DestFileNum As Integer, i As Integer
     Dim ColSize As Long

     On Error GoTo ErrRead
     ReadDB = False

     'If Dir(ImgFile) <> "" Then Kill ImgFile

     DestFileNum = FreeFile
     Open ImgFile For Binary As #DestFileNum

     ColSize = Col.ActualSize
     NumBlocks = ColSize \ BlockSize
     LeftOver = ColSize Mod BlockSize

     ReDim byteData(LeftOver)
     byteData() = Col.GetChunk(LeftOver)
     Put DestFileNum, , byteData()
     ReDim byteData(BlockSize)
     For i = 1 To NumBlocks
     byteData() = Col.GetChunk(BlockSize)
     Put #DestFileNum, , byteData()
     Next
     If LOF(DestFileNum) > 200 Then ReadDB = True
     Close #DestFileNum
     Exit Function

    ErrRead:
     MsgBox "READ PICTURE ERR:" & Err.Number
     ReadDB = False
     Exit Function
    End Function//如果ReadDB=False则写文件失败。

http://community.csdn.net/Expert/TopicView3.asp?id=4767614

使用流对象保存和显示图片
打开vb6,新建工程。添加两个按钮,一个image控件
注意:Access中的photo字段类型为OLE对象.
SqlServer中的photo字段类型为Image'** 引用 Microsoft ActiveX Data Objects 2.5 Library 及以上版本
‘2.5版本以下不支持Stream对象
Dim iConcstr As String
Dim iConc As ADODB.Connection
'保存文件到数据库中
Sub s_SaveFile()
    Dim iStm As ADODB.Stream
    Dim iRe As ADODB.Recordset
    Dim iConcstr As String    '读取文件到内容
    Set iStm = New ADODB.Stream
    With iStm
        .Type = adTypeBinary   '二进制模式
        .Open
        .LoadFromFile App.Path + "\test.jpg"
    End With
       '打开保存文件的表
    Set iRe = New ADODB.Recordset
    With iRe
        .Open "select * from img", iConc, 1, 3
        .AddNew         '新增一条记录
        .Fields("photo") = iStm.Read
        .Update
    End With
      '完成后关闭对象
    iRe.Close
    iStm.Close
End Sub
Sub s_ReadFile()
    Dim iStm As ADODB.Stream
    Dim iRe As ADODB.Recordset
    '打开表
Set iRe = New ADODB.Recordset
‘得到最新添加的纪录
    iRe.Open "select top 1 * from img order by id desc", iConc, adOpenKeyset, adLockReadOnly
    '保存到文件
    Set iStm = New ADODB.Stream
    With iStm
        .Mode = adModeReadWrite
        .Type = adTypeBinary
        .Open
        .Write iRe("photo")
‘这里注意了,如果当前目录下存在test1.jpg,会报一个文件写入失败的错误.
        .SaveToFile App.Path & "\test1.jpg"
    End With
       Image1.Picture = LoadPicture(App.Path & "\test1.jpg")
   '关闭对象
    iRe.Close
    iStm.Close
End Sub
Private Sub Command1_Click()
Call s_ReadFile
End Sub
Private Sub Command2_Click()
Call s_SaveFile
End Sub
Private Sub Form_Load()
    '数据库连接字符串
    iConcstr = "Provider=Microsoft.Jet.OLEDB.4.0;Persist Security Info=False" & _
        ";Data Source=F:\csdn_vb\database\保存图片\access图片\img.mdb"‘下面的语句是连接sqlserver数据库的.
    ‘iConcstr = "Provider=SQLOLEDB.1;Persist Security Info=True;" & _
‘ "User ID=sa;Password=;Initial Catalog=test;Data Source=yang"
    Set iConc = New ADODB.Connection
   iConc.Open iConcstr
End Sub
Private Sub Form_Unload(Cancel As Integer)
iConc.Close
Set iConc = Nothing
End Sub

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'追加图片到数据库
Public Function savebmptodb(ByVal strdh As String, ByVal ypbh As Long, ByVal sfilename As String) As Boolean
On Error GoTo err
    savebmptodb = False
    Dim strStream As New ADODB.Stream
    Dim rs As New ADODB.Recordset
    strStream.Type = adTypeBinary
    strStream.Open
    strStream.LoadFromFile sfilename
    Dim strsql As String
    strsql = "select * from tb_images where strdh='" & strdh & "' and ypbh=" & ypbh
    rs.Open strsql, g_pubcnn, adOpenStatic, adLockOptimistic
    If rs.RecordCount <= 0 Then
        rs.AddNew
    End If

    rs.Fields("bmp").Value = strStream.Read
    rs.Fields("ypbh").Value = ypbh
    rs.Fields("strdh").Value = strdh
    rs.Fields("flname").Value = strdh & ypbh
    rs.update
    savebmptodb = True


err:
    strStream.Close
    Set strStream = Nothing
   PubCloseRecord rs, True
End Function

调试易

如何用VB+SQL保存,读取数据库中的图片

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