Visual Basic到ms。访问问题，请帮忙 [英] Visual basic to ms. Access problem, please help

问题描述

我的问题很简单，我尝试更新数据（日期类型）以使用datetimepicker访问数据库，任何帮助将不胜感激。谢谢



我尝试过：

 Private Sub btnEdit_Click（sender as Object，e As EventArgs）处理btnEdit.Click 
 StrSql =（update [borrowstable] set bookcode ='& Trim（txtbookcode.Text）&'，membernum =' & Trim（membernum.Text）&'，borrowdate ='& Trim（datetimepicker.text）&'where borrowid =& txtborrowid.Text&）
 objCommand =新的OleDbCommand 
 objCommand.Connection = Myconnection.Open 
 objCommand.CommandType = CommandType.Text 
 objCommand.CommandText = StrSql 
 objDataAdapter = New OleDbDataAdapter（objCommand）
 objDataAdapter。 Fill（objDataSet，Mdt_borrowstable）
 objCommand.ExecuteNonQuery（）
 Myconnection.Close（）
 MsgBox（Succed。，MsgBoxStyle.Information）
 browse（）
 End Sub 

解决方案

不要做我那样的！

永远不要连接字符串来构建SQL命令。它让您对意外或故意的SQL注入攻击持开放态度，这可能会破坏您的整个数据库。改为使用参数化查询。



连接字符串时会导致问题，因为SQL会收到如下命令：

  SELECT  *  FROM  MyTable  WHERE  StreetAddress = '  Baker' s Wood '   

就SQL而言，用户添加的引号会终止字符串，并且您会遇到问题。但情况可能更糟。如果我来并改为输入：x'; DROP TABLE MyTable; - 然后SQL收到一个非常不同的命令：

  SELECT  *  FROM  MyTable  WHERE  StreetAddress = '  x';  DROP  表 MyTable;   -   ' 

哪个SQL看作三个单独的命令：

  SELECT  *  FROM  MyTable  WHERE  StreetAddress = '  x'; 

完全有效的SELECT

  DROP   TABLE  MyTable; 

完全有效的删除表格通讯和

   -   ' 

其他一切都是评论。

所以它确实：选择任何匹配的行，从数据库中删除表，并忽略其他任何内容。



所以总是使用参数化查询！或者准备好经常从备份中恢复数据库。你经常定期备份，不是吗？



一旦你在整个应用中修复了这个问题，问题就会同时消失。 / BLOCKQUOTE>

my problem is simple, i try to update data (date type) to access database with datetimepicker, any help would be greatly appreciated. thanks

What I have tried:

Private Sub btnEdit_Click(sender As Object, e As EventArgs) Handles btnEdit.Click
        StrSql = ("update [borrowstable] set bookcode='" & Trim(txtbookcode.Text) & "',membernum='" & Trim(membernum.Text) & "',borrowdate='" & Trim(datetimepicker.text) & "' where borrowid=" & txtborrowid.Text & "")
        objCommand = New OleDbCommand
        objCommand.Connection = Myconnection.Open
        objCommand.CommandType = CommandType.Text
        objCommand.CommandText = StrSql
        objDataAdapter = New OleDbDataAdapter(objCommand)
        objDataAdapter.Fill(objDataSet, "Mdt_borrowstable")
        objCommand.ExecuteNonQuery()
        Myconnection.Close()
        MsgBox("Succed.", MsgBoxStyle.Information)
        browse()
    End Sub

解决方案

Don't do it like that!
Never concatenate strings to build a SQL command. It leaves you wide open to accidental or deliberate SQL Injection attack which can destroy your entire database. Use Parametrized queries instead.

When you concatenate strings, you cause problems because SQL receives commands like:

SELECT * FROM MyTable WHERE StreetAddress = 'Baker's Wood'

The quote the user added terminates the string as far as SQL is concerned and you get problems. But it could be worse. If I come along and type this instead: "x';DROP TABLE MyTable;--" Then SQL receives a very different command:

SELECT * FROM MyTable WHERE StreetAddress = 'x';DROP TABLE MyTable;--'

Which SQL sees as three separate commands:

SELECT * FROM MyTable WHERE StreetAddress = 'x';

A perfectly valid SELECT

DROP TABLE MyTable;

A perfectly valid "delete the table" command

--'

And everything else is a comment.
So it does: selects any matching rows, deletes the table from the DB, and ignores anything else.

So ALWAYS use parameterized queries! Or be prepared to restore your DB from backup frequently. You do take backups regularly, don't you?

The chances are that once you have fixed that throughout your app, the problem will disappear at the same time.

这篇关于Visual Basic到ms。访问问题，请帮忙的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！