在access数据库中,由于数据增加,数据库会膨胀,我们希望存档备份数据。
在不需要的旧数据情况下,例如数十万条记录,并且不断添加新记录。我们会把旧的不需要数据单独的保存在另外的数据库中。
执行过程包括以下步骤:
1. 开始一个事务。
2. 执行追加查询。
3. 执行delete查询。
4. 获取用户确认以提交更改。
5. 如果任何步骤出现错误,则回滚事务。
详细代码:
Sub DoArchive() On Error GoTo Err_DoArchive Dim ws As DAO.Workspace 'Current workspace (for transaction). Dim db As DAO.Database 'Inside the transaction. Dim bInTrans As Boolean 'Flag that transaction is active. Dim strSql As String 'Action query statements. Dim strMsg As String 'MsgBox message. ' Step 1: Initialize database object inside a transaction. Set ws = DBEngine(0) ws.BeginTrans bInTrans = True Set db = ws(0) ' Step 2: Execute the append. strSql = "INSERT INTO MyTable(Field1, Field2, Field3 ) " & "IN ""C:\MyData.accdb"" " & "SELECT 到货日期, 采购编码, 到达数量 FROM tblPurchaseDetail WHERE (MyYesNoField = True) " db.Execute strSql, dbFailOnError ' Step 3: Execute the delete. strSql = "DELETE FROM tblPurchaseDetail WHERE (MyYesNoField = True)" db.Execute strSql, dbFailOnError ' Step 4: Get user Confirmation to commit the change. strMsg = "Archive " & db.RecordsAffected & " record(s)?" If MsgBox(strMsg, vbOKCancel vbQuestion, "Confirm") = vbOK Then ws.CommitTrans bInTrans = False End If Exit_DoArchive: ' Step 5: Clean up On Error Resume Next Set db = Nothing If bInTrans Then 'Rollback if the transaction is active. ws.Rollback End If Set ws = Nothing Exit Sub Err_DoArchive: MsgBox Err.Description, vbExclamation, "Archiving failed: Error " & Err.Number Resume Exit_DoArchive End Sub
把数据库的旧数据添加到C:\Mydata数据库中
更多的access技巧源码,请关注office交流网:http://www.office-cn.net