Save 和 Open 方法范例 (VB)

<p><font face="Verdana">Save 和 Open 方法范例 (VB)</font></p><font face="Verdana">
<p><br/>这三个范例演示如何配合使用 Save 和 Open 方法。</p>
<p>假设用户在出差时需要携带数据库中的一个表。在出发前，用户以 Recordset 访问数据，并将其保存为便携格式。在到达目的地后，用户以本地、断开连接的方式访问 Recordset，在修改 Recordset 后将其保存。最后，当用户回家后，再次连接数据库并用旅途中所做的更改对其进行更新。</p>
<p><br/>Public Sub Main()<br/>&nbsp;&nbsp;&nbsp; SaveX1<br/>&nbsp;&nbsp;&nbsp; SaveX2<br/>&nbsp;&nbsp;&nbsp; SaveX3<br/>End Sub</p>
<p>首先，访问并保存 Authors 表。</p>
<p>Public Sub SaveX1()<br/>Dim rst As ADODB.Recordset<br/>Set rst = New ADODB.Recordset</p>
<p>rst.Open "SELECT au_id, au_lname, au_fname, phone FROM Authors", _<br/>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; "Provider=SQLOLEDB;Data Source=MySrvr;User Id=uid;" &amp; _<br/>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; "Password=pwd;Initial Catalog=pubs;" _<br/>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; adOpenDynamic, adLockOptimistic, adCmdText</p>
<p>'For sake of illustration, save the Recordset to a diskette in XML<br/>'format.<br/>rst.Save "a:\Pubs.xml", adPersistXML</p>
<p>rst.Close<br/>End Sub</p>
<p>现在用户已到达目的地。以本地、断开连接的 Recordset 访问 Authors 表。请注意，要访问保存的文件 a:\Pubs.xml，必须在用户使用的机器上装有 MSPersist 提供者。</p>
<p>Public Sub SaveX2()<br/>Dim rst As ADODB.Recordset<br/>Set rst = New ADODB.Recordset</p>
<p>'For sake of illustration, we specIFy all parameters.<br/>rst.Open "a:\Pubs.xml", "Provider=MSPersist;", , , adCmdFile</p>
<p>'Now you have a local, disconnected Recordset. Edit it as you desire.<br/>'(In this example, the change makes no difference).<br/>rst.Find "au_lname = 'Carson'"<br/>If rst.EOF Then<br/>&nbsp;&nbsp;&nbsp; debug.Print "Name not found."<br/>&nbsp;&nbsp;&nbsp; Exit Sub<br/>End If</p>
<p>rst!city = "Berkeley"<br/>rst.Update</p>
<p>'Save changes in ADTG format this time, purely for sake of illustration.<br/>'Note that the previous version is still on the diskette, as a:\Pubs.xml.<br/>rst.Save "a:\Pubs.adtg", adPersistADTG<br/>rst.Close<br/>End Sub</p>
<p>最后用户回到家里。现在用所做的更改更新数据库。</p>
<p>Public Sub SaveX3()<br/>Dim cnn As New ADODB.Connection<br/>Dim rst As ADODB.Recordset<br/>Set rst = New ADODB.Recordset</p>
<p>'If there is no ActiveConnection, you can open with defaults.<br/>rst.Open "a:\Pubs.adtg"</p>
<p>'Connect to the database, associate the Recordset with the connection, <br/>'then update the database table with the changed Recordset.<br/>cnn.Open "Provider=SQLOLEDB;Data Source=MySrvr;User Id=uid;" &amp; _<br/>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; "Password=pwd;Initial Catalog=pubs;"<br/>rst.ActiveConnection = cnn<br/>rst.UpdateBatch</p>
<p>rst.Close<br/>cnn.Close<br/>End Sub</p>
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