使用VB.NET将数据插入MySQL表 [英] Inserting data into a MySQL table using VB.NET

问题描述

使用VB.NET应用程序将数据插入MySQL数据库中的表时遇到问题. 我有一个简单的表单，当我在文本框中设置一些数据并按GO按钮时，代码应执行一个名为InsertCar()的函数，该函数接受所有这些值并将其插入数据库，然后在事务为成功完成，否则返回false.我的问题是表中没有任何内容.

I have a problem inserting data into a table on a MySQL database using a VB.NET application. I have a simple form where when I set some data to the textboxes and I press a GO button, the code should execute a function called InsertCar() that takes all these values and insert them into the database and then return true if the transaction is done successfully or false otherwise. My problem is that nothing is being inserted into the table.

Imports MySql.Data.MySqlClient
Imports System.Data.Sql
Imports System
Imports System.Data

Public Class Form1

Dim connectionString As String = "Server=localhost; User Id=root; Password=123456; Database=uni_park_db"
Dim SQLConnection As MySqlConnection = New MySqlConnection
Dim oDt_sched As New DataTable()

//SOME CODE For other buttons//


//Code for a button where the InsertCar() function is called at the beginning//


Public Function InsertCar() As Boolean

    SQLConnection = New MySqlConnection()
    SQLConnection.ConnectionString = connectionString
    Dim sqlCommand As New MySqlCommand
    Dim str_carSql As String

    Try
        str_carSql = "insert into members_car (car_id, member_id, model, color, chassis_id, plate_number, code) values ('" + TextBox20.Text + "','" + TextBox20.Text + "','" + TextBox23.Text + "','" + TextBox24.Text + "','" + TextBox22.Text + "','" + TextBox21.Text + "','" + ComboBox1.SelectedItem + "')"
        MsgBox(str_carSql)
        sqlCommand.Connection = SQLConnection
        sqlCommand.CommandText = str_carSql
        sqlCommand.ExecuteNonQuery()

        Return True

    Catch ex As Exception
        Return False
        MsgBox("Error occured: Could not insert record")
    End Try

End Function


End Class

我正在使用此MsgBox(str_carSql)来测试SQL语句是否正确和正确.

I am using this MsgBox(str_carSql) to test if the SQL statement is correct and it is correct.

任何帮助将不胜感激.

更新

我做了以下操作，但仍然无法正常工作

I did the following and it stills not working

Public Function InsertCar() As Boolean

    SQLConnection = New MySqlConnection()
    SQLConnection.ConnectionString = connectionString
    SQLConnection.Open()
    Dim sqlCommand As New MySqlCommand
    Dim str_carSql As String

    Try

        str_carSql = "insert into members_car (car_id, member_id, model, color, chassis_id, plate_number, code) values (@id,@m_id,@model,@color,@ch_id,@pt_num,@code)"
        sqlCommand.Connection = SQLConnection
        sqlCommand.CommandText = str_carSql
        sqlCommand.Parameters.AddWithValue("@id", TextBox20.Text)
        sqlCommand.Parameters.AddWithValue("@m_id", TextBox20.Text)
        sqlCommand.Parameters.AddWithValue("@model", TextBox23.Text)
        sqlCommand.Parameters.AddWithValue("@color", TextBox24.Text)
        sqlCommand.Parameters.AddWithValue("@ch_id", TextBox22.Text)
        sqlCommand.Parameters.AddWithValue("@pt_num", TextBox21.Text)
        sqlCommand.Parameters.AddWithValue("@code", ComboBox1.SelectedItem)
        sqlCommand.ExecuteNonQuery()

        Return True

    Catch ex As Exception
        Return False
        MsgBox("Error occured: Could not insert record")
    End Try

End Function

更新

插入程序也不起作用，我将发布整个代码，也许在其他地方发现了问题

The Insert is not working either, I will post the entire code maybe a problem is found elsewhere

导入MySql.Data.MySqlClient 导入System.Data.Sql 进口制度 导入System.Data

Imports MySql.Data.MySqlClient Imports System.Data.Sql Imports System Imports System.Data

公共类表格1

Dim connectionString As String = "Server=localhost; User Id=root; Password=123456; Database=uni_park_db"
Dim SQLConnection As MySqlConnection = New MySqlConnection
Dim oDt_sched As New DataTable()

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

    Try


        If SQLConnection.State = ConnectionState.Open Then
            If TextBox1.Text = "" Then
                MsgBox("Please Input a Valid ID")
            Else
                Dim myAdapter1 As New MySqlDataAdapter("select m.work_date as Work, m.time_in as Start, m.time_out as End from university_members as u inner join members_schedule as m on u.members_schedule_id=m.members_schedule_id where member_id = " & TextBox1.Text, SQLConnection)
                Dim myAdapter As New MySqlDataAdapter("select member_id, first_name, last_name, type from university_members, members_schedule where(university_members.members_schedule_id = members_schedule.members_schedule_id) AND member_id = " & TextBox1.Text, SQLConnection)
                Dim mydatatable As New DataTable()
                Dim dataset As New DataSet()
                myAdapter.Fill(mydatatable)

                If (mydatatable.Rows.Count > 0 And myAdapter1.Fill(dataset)) Then
                    TextBox2.Text = mydatatable.Rows(0).Item("first_name")
                    TextBox3.Text = mydatatable.Rows(0).Item("last_name")
                    TextBox4.Text = mydatatable.Rows(0).Item("type")
                    TextBox20.Text = mydatatable.Rows(0).Item("member_id")
                    DataGridView1.DataSource = dataset.Tables(0)
                    oDt_sched = dataset.Tables(0)

                Else
                    MsgBox("Check Error: ID Not Found! Enter a Valid ID")
                    TextBox1.Text = "Example 123456 "
                    TextBox2.Text = " "
                    TextBox3.Text = " "
                    TextBox4.Text = " "
                End If
            End If
        Else
            MsgBox("Database Connection Error: Database Connection Not Established. Please Connect First.")
        End If



    Catch ex As Exception
        MsgBox(ex.ToString)

    End Try


End Sub



Private Sub ExitToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ExitToolStripMenuItem.Click
    Application.Exit()
End Sub


Private Sub DatabaseConnectToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles DatabaseConnectToolStripMenuItem.Click

    SQLConnection = New MySqlConnection()
    SQLConnection.ConnectionString = connectionString
    Try

        If SQLConnection.State = ConnectionState.Closed Then
            SQLConnection.Open()
            MsgBox("Database Connection Sccessfully Established")
        Else
            SQLConnection.Close()
            MsgBox("Database Connection Terminated")

        End If
    Catch ex As Exception
        MsgBox(ex.ToString)

    End Try

End Sub



Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click

    TextBox1.Text = "Example 123456 "
    TextBox2.Text = " "
    TextBox3.Text = " "
    TextBox4.Text = " "
    DataGridView1.Columns.Clear()
    DataGridView1.DataSource = Nothing


End Sub


Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click


    Dim str_sql As String = ""
    Dim obj_msadapter As MySqlDataAdapter
    Dim i_maxh As Integer
    Dim i_beginh As Integer
    Dim ods_avail As DataSet = New DataSet()
    Dim str_err As String = ""
    Dim i_strth As Integer
    Dim odt_avail As New DataTable()
    Dim odrcol_avail() As DataRow
    Dim str_range As String = ""

    Try

        'perform insert car here (boolean to see if the code continues running)

        ''''''''''''''''''''''''''

        If InsertCar() Then
            For Each odr As DataRow In oDt_sched.Rows
                i_maxh = odr(2)
                i_beginh = odr(1)
                i_strth = odr(1) + 2
                str_range = ""

                str_sql = "select * from parked_cars where pwork_date='" & odr(0).ToString() & "'"

                ods_avail = New DataSet()
                obj_msadapter = New MySqlDataAdapter(str_sql, SQLConnection)
                obj_msadapter.Fill(ods_avail)

                odt_avail = ods_avail.Tables(0)

                If odt_avail.Rows.Count < 210 Then
                    While (i_strth <= i_maxh)
                        odrcol_avail = odt_avail.Select("ptime_in='" + i_beginh.ToString() + "' and ptime_out='" + i_strth.ToString() + "'")

                        If odrcol_avail.Count < 30 Then
                            str_range += i_beginh.ToString() + ";" + i_strth.ToString()
                        Else
                            str_range += "0"
                        End If

                        i_strth += 2
                        i_beginh += 2
                    End While

                    FillSpots(str_range, odr(0).ToString())
                Else
                    str_err += "no place on day: " + odr(0).ToString() + ";"
                    MsgBox("No place is found on this day")
                End If

            Next
        End If
    Catch ex As Exception
        MsgBox("")

    End Try
End Sub

Public Function FillSpots(ByVal blowf As String, ByVal _day As String) As Boolean

    Dim str_unit As String
    Dim i_count As Integer = 0
    Dim str_i_strt As String
    Dim str_i_end As String
    Dim str_sql As String

    Try
        For Each str_unit In blowf.Split("0")
            If str_unit <> "" Then
                str_i_strt = str_unit.Split(";")(0)
                str_i_end = str_unit.Split(";")(str_unit.Split(";").Length - 1)
                str_sql = "insert into parked_cars values ('" + TextBox20.Text + "','" + _day + "','" + str_i_strt + "','" + str_i_end + "')"
            End If
        Next

        Return True
    Catch ex As Exception
        Throw ex
    End Try
End Function


Public Function InsertCar() As Boolean

    SQLConnection = New MySqlConnection()
    SQLConnection.ConnectionString = connectionString
    SQLConnection.Open()
    Dim sqlCommand As New MySqlCommand
    Dim str_carSql As String

    Try

        str_carSql = "insert into members_car (car_id, member_id, model, color, chassis_id, plate_number, code) values (?id,?m_id,?model,?color,?ch_id,?pt_num,?code)"
        sqlCommand.Connection = SQLConnection
        sqlCommand.CommandText = str_carSql
        sqlCommand.CommandType = CommandType.Text
        sqlCommand.Parameters.AddWithValue("?id", TextBox20.Text)
        sqlCommand.Parameters.AddWithValue("?m_id", TextBox20.Text)
        sqlCommand.Parameters.AddWithValue("?model", TextBox23.Text)
        sqlCommand.Parameters.AddWithValue("?color", TextBox24.Text)
        sqlCommand.Parameters.AddWithValue("?ch_id", TextBox22.Text)
        sqlCommand.Parameters.AddWithValue("?pt_num", TextBox21.Text)
        sqlCommand.Parameters.AddWithValue("?code", ComboBox1.SelectedItem)
        sqlCommand.ExecuteNonQuery()

        Return True

    Catch ex As Exception
        Return False
        MsgBox("Error occured: Could not insert record")
    End Try

End Function



Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click

    ComboBox1.ResetText()
    TextBox21.Text = " "
    TextBox22.Text = " "
    TextBox23.Text = " "
    TextBox24.Text = " "
    DataGridView2.Columns.Clear()
    DataGridView2.DataSource = Nothing

End Sub

结束班级

感谢大家的帮助.这是对我有用的解决方案

Thanks everyone for the help. This is the solution that worked for me

    Dim iReturn as boolean
    Using SQLConnection As New MySqlConnection(connectionString)
        Using sqlCommand As New MySqlCommand()
            With sqlCommand
                .CommandText = "INSERT INTO members_car (`car_id`, `member_id`, `model`, `color`, `chassis_id`, `plate_number`, `code`) values (@xid,@m_id,@imodel,@icolor,@ch_id,@pt_num,@icode)"
                .Connection = SQLConnection
                .CommandType = CommandType.Text // You missed this line
                .Parameters.AddWithValue("@xid", TextBox20.Text)
                .Parameters.AddWithValue("@m_id", TextBox20.Text)
                .Parameters.AddWithValue("@imodel", TextBox23.Text)
                .Parameters.AddWithValue("@icolor", TextBox24.Text)
                .Parameters.AddWithValue("@ch_id", TextBox22.Text)
                .Parameters.AddWithValue("@pt_num", TextBox21.Text)
                .Parameters.AddWithValue("@icode", ComboBox1.SelectedItem)

            End With
            Try
                SQLConnection.Open()
                sqlCommand.ExecuteNonQuery()
                iReturn = TRUE
            Catch ex As MySqlException
                MsgBox ex.Message.ToString
                iReturn = False
            Finally
                SQLConnection.Close()
            End Try
        End Using
    End Using

   Return iReturn

推荐答案

实例化连接后，将其打开.

After instantiating the connection, open it.

  SQLConnection = New MySqlConnection()
  SQLConnection.ConnectionString = connectionString
  SQLConnection.Open()

此外，避免仅通过附加字符串来构建SQL语句.如果使用参数，则更好，这样可以提高性能，使程序不易于受到SQL注入攻击，并且程序更稳定.例如:

Also, avoid building SQL statements by just appending strings. It's better if you use parameters, that way you win on performance, your program is not prone to SQL injection attacks and your program is more stable. For example:

 str_carSql = "insert into members_car 
               (car_id, member_id, model, color, chassis_id, plate_number, code) 
               values 
               (@id,@m_id,@model,@color,@ch_id,@pt_num,@code)"

然后您执行以下操作:

sqlCommand.Parameters.AddWithValue("@id",TextBox20.Text)
sqlCommand.Parameters.AddWithValue("@m_id",TextBox23.Text)
' And so on... 

然后您致电:

sqlCommand.ExecuteNonQuery()

这篇关于使用VB.NET将数据插入MySQL表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！