如何使用访问数据库解决VB.NET中的语法错误 [英] How do I solve syntax error in VB.NET with access database

问题描述

伙计们，请帮我解决从VB.net访问数据时出现的语法错误



我尝试了什么：

Guys, please help me solve this syntax error when inserting data into access from VB.net

What I have tried:

Private Sub btnSaveClient_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSaveClient.Click
        'Validating form controls to check the NULL
        If Len(Trim(btnGenerateID.Text)) = 0 Then
            MessageBox.Show("Click The Blue Button to Generate Client ID", "Input Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
            Exit Sub
            btnGenerateID.Focus()
        End If

        If Len(Trim(dtpRegtrationDate.Text)) = 0 Then
            MessageBox.Show("Eneter Registration Date", "Input Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
            Exit Sub
            dtpRegtrationDate.Focus()
        End If


        If Len(Trim(cmbPhoneStatus.Text)) = 0 Then
            MessageBox.Show("Choos Phone Status", "Input Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
            Exit Sub
            cmbPhoneStatus.Focus()
        End If

        If Len(Trim(cmbBrandStatus.Text)) = 0 Then
            MessageBox.Show("Chooce Brand Status", "Input Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
            Exit Sub
            cmbBrandStatus.Focus()
        End If

        If Len(Trim(cmbCategory.Text)) = 0 Then
            MessageBox.Show("Chooce Category", "Input Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
            Exit Sub
            cmbCategory.Focus()
        End If

        If Len(Trim(txtPhoneType.Text)) = 0 Then
            MessageBox.Show("Enter Phone Model", "Input Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
            Exit Sub
            txtPhoneType.Focus()
        End If

        If Len(Trim(CmbSIM.Text)) = 0 Then
            MessageBox.Show("Chooce SIM Yes/No", "Input Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
            Exit Sub
            CmbSIM.Focus()
        End If

        If Len(Trim(CmbSDCard.Text)) = 0 Then
            MessageBox.Show("Chooce SD Card Yes/No", "Input Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
            Exit Sub
            CmbSDCard.Focus()
        End If

        If Len(Trim(txtClientID.Text)) = 0 Then
            MessageBox.Show("Click Client ID", "Input Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
            Exit Sub
            txtClientID.Focus()
        End If

        If Len(Trim(txtClientName.Text)) = 0 Then
            MessageBox.Show("Enter Client Name", "Input Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
            Exit Sub
            txtClientName.Focus()
        End If

        If Len(Trim(cmbGender.Text)) = 0 Then
            MessageBox.Show("Chooce Gender", "Input Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
            Exit Sub
            cmbGender.Focus()
        End If

        If Len(Trim(txtLocation.Text)) = 0 Then
            MessageBox.Show("Enter Location", "Input Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
            Exit Sub
            txtLocation.Focus()
        End If

        If Len(Trim(txtContact1.Text)) = 0 Then
            MessageBox.Show("Enter 1st Contact ", "Input Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
            Exit Sub
            txtContact1.Focus()
        End If

        If Len(Trim(txtContact2.Text)) = 0 Then
            MessageBox.Show("Enter 2nd Contact", "Input Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
            Exit Sub
            txtContact1.Focus()
        End If

        If Len(Trim(txtRemarks.Text)) = 0 Then
            MessageBox.Show("Enter Remarks", "Input Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
            Exit Sub
            txtRemarks.Focus()
        End If

        Try
            'Writing SQL statement to insert the values into the Database
            sql = "INSERT INTO Client Registration VALUES ('" & txtClientID.Text & "','" & dtpRegtrationDate.Text & "','" & cmbPhoneStatus.Text & "','" & cmbBrandStatus.Text & "','" & cmbCategory.Text & "','" & CmbSIM.Text & "','" & CmbSDCard.Text & "','" & txtClientName.Text & "','" & cmbGender.Text & "','" & txtLocation.Text & "','" & txtPhoneType.Text & "','" & txtContact1.Text & "','" & txtContact2.Text & "','" & txtRemarks.Text & "')"
            ''" & str & "'
            da = New OleDb.OleDbDataAdapter(sql, con)
            da.Fill(ds, "Client Registration")
            MessageBox.Show("Client Registration Sucessfully Completed", "Success", MessageBoxButtons.OK, MessageBoxIcon.Information)

            clear()       ' Calling clear method to clear the form controls
        Catch ex As Exception
            MessageBox.Show(ex.Message, "Exception generated", MessageBoxButtons.OK, MessageBoxIcon.Error)
        End Try
    End Sub

推荐答案

不是那样的！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。总是使用参数化查询。



连接字符串时会导致问题，因为SQL会收到如下命令：

Not 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. Always use Parameterized queries instead.

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

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：

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;--'

哪个SQL看作三个单独的命令：

Which SQL sees as three separate commands:

SELECT * FROM MyTable WHERE StreetAddress = 'x';

完全有效的SELECT

A perfectly valid SELECT

DROP TABLE MyTable;

完全有效的删除表格通讯和

A perfectly valid "delete the table" command

--'

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。你定期做备份，不是吗？



当你修复整个应用程序以防止这种情况时，你可能会发现你现有的问题已经消失了好吧......

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?

By the time you have fixed your entire app to prevent this, you will probably find your existing problem has disappeared as well...

sql = "INSERT INTO Client Registration VALUES ('" & txtClientID.Text & "','" & dtpRegtrationDate.Text & "','" & cmbPhoneStatus.Text & "','" & cmbBrandStatus.Text & "','" & cmbCategory.Text & "','" & CmbSIM.Text & "','" & CmbSDCard.Text & "','" & txtClientName.Text & "','" & cmbGender.Text & "','" & txtLocation.Text & "','" & txtPhoneType.Text & "','" & txtContact1.Text & "','" & txtContact2.Text & "','" & txtRemarks.Text & "')"

永远不要建立一个通过连接字符串进行SQL查询。迟早，您将使用用户输入来执行此操作，这会打开一个名为SQL注入的漏洞，这对您的数据库很容易并且容易出错。

名称中的单引号你的程序崩溃。如果用户输入像Brian O'Conner这样的名称可能会使您的应用程序崩溃，那么这是一个SQL注入漏洞，崩溃是最少的问题，恶意用户输入，并且它被提升为具有所有凭据的SQL命令。

SQL注入 - 维基百科 [ ^ ]

SQL注入 [ ^ ]

按示例进行SQL注入攻击 [ ^ ]

PHP：SQL注入 - 手册 [ ^ ]

SQL注入预防备忘单 - OWASP [ ^ ]

我该怎么办？解释没有技术术语的SQL注入？ - 信息安全堆栈交换 [ ^ ]

Never build an SQL query by concatenating strings. Sooner or later, you will do it with user inputs, and this opens door to a vulnerability named "SQL injection", it is dangerous for your database and error prone.
A single quote in a name and your program crash. If a user input a name like "Brian O'Conner" can crash your app, it is an SQL injection vulnerability, and the crash is the least of the problems, a malicious user input and it is promoted to SQL commands with all credentials.
SQL injection - Wikipedia[^]
SQL Injection[^]
SQL Injection Attacks by Example[^]
PHP: SQL Injection - Manual[^]
SQL Injection Prevention Cheat Sheet - OWASP[^]
How can I explain SQL injection without technical jargon? - Information Security Stack Exchange[^]

在调试模式下运行，在构建查询后放入断点，复制查询并在访问中运行它看看它说的是什么。

Run in debug mode, put a breakpoint in after you have built your query, copy the query and run it in access and see what it says.

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