'VB/VBA中實現數據庫中的文件存取

'示例數據庫為ACCESS數據庫,用SQL數據庫的話,只需要改連接字符串
'
'*************************************************************************
'**
'** 使用 ADODB.Stream 保存/讀取文件到數據庫
'** 引用 Microsoft ActiveX Data Objects 2.5 Library 及以上版本
'**
'** ----- 數據庫連接字符串模板 ---------------------------------------
'** ACCESS數據庫
'** iConcStr = "Provider=Microsoft.Jet.OLEDB.4.0;Persist Security Info=False" & _
'**     ";Data Source=數據庫名"
'**
'** SQL數據庫
'** iConcStr = "Provider=SQLOLEDB.1;Persist Security Info=True;" & _
'**     "User ID=用戶名;Password=密碼;Initial Catalog=數據庫名;Data Source=SQL服務器名"
'**
'*************************************************************************
'
'保存文件到數據庫中
Sub s_SaveFile()
    Dim iStm As ADODB.Stream
    Dim iRe As ADODB.Recordset
    Dim iConcStr As String
    
    'ACCESS數據庫的連接字符串
    iConcStr = "Provider=Microsoft.Jet.OLEDB.4.0;Persist Security Info=False" & _
        ";Data Source=F:\My Documents\客戶資料1.mdb"
    
	'SQL數據庫的連接字符串
    iConcStr = "Provider=SQLOLEDB.1;Persist Security Info=True;" & _
        "User ID=用戶名;Password=密碼;Initial Catalog=數據庫名;Data Source=SQL服務器名"
    '讀取文件到內容
    Set iStm = New ADODB.Stream
    With iStm
        .Type = adTypeBinary    '二進制模式,如果是用text/ntext字段保存純文本數據,則改用 adTypeText
        .Open
        .LoadFromFile "c:\test.doc"
    End With
    
    '打開保存文件的表
    Set iRe = New ADODB.Recordset
    With iRe
        .Open "表", iConc, adOpenKeyset, adLockOptimistic
        .AddNew         '新增一條記錄
        .Fields("保存文件內容的字段") = iStm.Read
        .Update
    End With
    
    '完成后關閉對象
    iRe.Close
    iStm.Close
End Sub

'從數據庫中讀取數據,保存成文件
Sub s_ReadFile()
    Dim iStm As ADODB.Stream
    Dim iRe As ADODB.Recordset
    Dim iConc As String
    
    '數據庫連接字符串
    iConc = "Provider=Microsoft.Jet.OLEDB.4.0;Persist Security Info=False" & _
        ";Data Source=\\xz\c$\Inetpub\zj\zj\zj.mdb"
    
    '打開表
    Set iRe = New ADODB.Recordset
    iRe.Open "tb_img", iConc, adOpenKeyset, adLockReadOnly
    iRe.Filter = "id=64"

    if iRe("img").ActualSize>0 Then

	    '保存到文件
	    Set iStm = New ADODB.Stream
	    With iStm
	        .Mode = adModeReadWrite
	        .Type = adTypeBinary '二進制模式,如果是用text/ntext字段保存純文本數據,則改用 adTypeText
	        .Open
	        .Write iRe("img")
	        .SaveToFile "c:\test.doc"
	    End With
    
	    '關閉對象
	    iStm.Close
	End If

    iRe.Close
End Sub