how to write update code vb.net and sql geeks - mysql

Question

I wrote this update code for mysql server using vb.net and its not working.
Dim sqlstring = "Update initial_nom set f_name = '" &
TextBox1.Text & "',s_name = '" &
TextBox2.Text & "',th_name = '" &
TextBox3.Text & "',fo_name = '" &
TextBox4 & "',adm_type = '" &
ComboBox4.SelectedItem.ToString() & "'
where (app_no = " & TextBox5.Text & ")"
cmd.ExecuteNonQuery()

Answer 1

Try this:
Dim connectionString As String = "Server=my_server;Database=my_db;Uid=my_username;Pwd=my_password;"
Dim SQLConnection As New MySqlConnection(connectionString)
Dim SQLCommand As New MySqlCommand()
With SQLCommand
.CommandText = "UPDATE initial_nom SET f_name = #f_name, s_name = #s_name, th_name = #th_name, fo_name = #fo_name, adm_type = #adm_type WHERE app_no = #app_no"
.Connection = SQLConnection
.Parameters.AddWithValue("#f_name", TextBox1.Text)
.Parameters.AddWithValue("#s_name", TextBox2.Text)
.Parameters.AddWithValue("#th_name", TextBox3.Text)
.Parameters.AddWithValue("#fo_name", TextBox4.Text)
.Parameters.AddWithValue("#app_no", TextBox5.Text)
.Parameters.AddWithValue("#adm_type", ComboBox4.SelectedItem.ToString)
End With
Try
SQLConnection.Open()
SQLCommand.ExecuteNonQuery()
Catch ex As MySqlException
MsgBox(ex.Message.ToString)
Finally
SQLConnection.Close()
End Try
Don't forget to enter your own details in the connection string.
In answer to your other closed question, this should do what you want:
Dim connectionString As String = "Server=my_server;Database=my_db;Uid=my_username;Pwd=my_password;"
Dim SQLConnection As New MySqlConnection(connectionString)
Dim SQLCommand As New MySqlCommand()
With SQLCommand
.CommandText = "INSERT INTO nomination (f_name, s_name, th_name, fo_name, app_no, adm_type) values (#f_name, #s_name, #th_name, #fo_name, #app_no, #adm_type)"
.Connection = SQLConnection
.Parameters.AddWithValue("#f_name", TextBox1.Text)
.Parameters.AddWithValue("#s_name", TextBox2.Text)
.Parameters.AddWithValue("#th_name", TextBox3.Text)
.Parameters.AddWithValue("#fo_name", TextBox4.Text)
.Parameters.AddWithValue("#app_no", TextBox5.Text)
.Parameters.AddWithValue("#adm_type", ComboBox4.SelectedItem.ToString)
End With
Try
SQLConnection.Open()
SQLCommand.ExecuteNonQuery()
Catch ex As MySqlException
MsgBox(ex.Message.ToString)
Finally
SQLConnection.Close()
End Try
Update
I noticed in your other question that you were struggling with ADODB and a connection DSN, there is a far easier way to do this using the MySQL Connector.
Download and install the MySQL Connector from http://dev.mysql.com/downloads/connector/net/
You now need to add a reference to this in your project:
Select Browse and navigate to the Assemblies directory for the MySQL Connector:
Select MySQL.Data.dll and click Ok:
Now all you need to do is add Imports MySql.Data.MySqlClient to the very top of your form code and you will be able to access your database once you have created the correct connection string.
Here is some example code which will give you and idea of how you can perform some simple operations on your DB, this is tested and working (I was bored this morning!).
Imports MySql.Data.MySqlClient
Public Class Form1
Dim connectionString As String = "Server=my_server;Database=my_db;Uid=my_username;Pwd=my_password;"
Dim SQLConnection As New MySqlConnection(connectionString)
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
For i As Integer = 0 To 5
ComboBox4.Items.Add(i)
Next
ComboBox4.SelectedIndex = 0
End Sub
Private Sub update_row()
Dim SQLCommand As New MySqlCommand()
With SQLCommand
.CommandText = "UPDATE nomination SET f_name = #f_name, s_name = #s_name, th_name = #th_name, fo_name = #fo_name, adm_type = #adm_type WHERE app_no = #app_no"
.Connection = SQLConnection
.Parameters.AddWithValue("#f_name", TextBox1.Text)
.Parameters.AddWithValue("#s_name", TextBox2.Text)
.Parameters.AddWithValue("#th_name", TextBox3.Text)
.Parameters.AddWithValue("#fo_name", TextBox4.Text)
.Parameters.AddWithValue("#app_no", TextBox5.Text)
.Parameters.AddWithValue("#adm_type", ComboBox4.SelectedItem.ToString)
End With
Try
SQLConnection.Open()
SQLCommand.ExecuteNonQuery()
Catch ex As MySqlException
MsgBox(ex.Message.ToString)
Finally
SQLConnection.Close()
End Try
End Sub
Private Sub insert_row()
Dim SQLCommand As New MySqlCommand()
With SQLCommand
.CommandText = "INSERT INTO nomination (f_name, s_name, th_name, fo_name, app_no, adm_type) values (#f_name, #s_name, #th_name, #fo_name, #app_no, #adm_type)"
.Connection = SQLConnection
.Parameters.AddWithValue("#f_name", TextBox1.Text)
.Parameters.AddWithValue("#s_name", TextBox2.Text)
.Parameters.AddWithValue("#th_name", TextBox3.Text)
.Parameters.AddWithValue("#fo_name", TextBox4.Text)
.Parameters.AddWithValue("#app_no", TextBox5.Text)
.Parameters.AddWithValue("#adm_type", ComboBox4.SelectedItem.ToString)
End With
Try
SQLConnection.Open()
SQLCommand.ExecuteNonQuery()
Catch ex As MySqlException
MsgBox(ex.Message.ToString)
Finally
SQLConnection.Close()
End Try
End Sub
Private Sub select_from()
Dim SQLCommand As New MySqlCommand
Dim SQLAdapter As New MySqlDataAdapter
Dim DTable As New DataTable
With SQLCommand
.CommandText = "SELECT * FROM nomination"
.Connection = SQLConnection
End With
Try
SQLConnection.Open()
SQLAdapter.SelectCommand = SQLCommand
SQLAdapter.Fill(DTable)
DataGridView1.DataSource = DTable
Catch ex As MySqlException
MsgBox(ex.Message.ToString)
Finally
SQLConnection.Close()
End Try
End Sub
Private Sub create_table()
Dim SQLCommand As New MySqlCommand
With SQLCommand
.CommandText = "CREATE TABLE nomination (f_name varchar(50),s_name varchar(50),th_name varchar(50),fo_name varchar(50),app_no varchar(50),adm_type varchar(50))"
.Connection = SQLConnection
End With
Try
SQLConnection.Open()
SQLCommand.ExecuteNonQuery()
Catch ex As MySqlException
MsgBox(ex.Message.ToString)
Finally
SQLConnection.Close()
End Try
End Sub
Private Sub drop_table()
If MsgBox("Are you really sure you want to DROP this table?", MsgBoxStyle.Question + MsgBoxStyle.YesNo) = MsgBoxResult.Yes Then
Dim SQLCommand As New MySqlCommand
With SQLCommand
.CommandText = "DROP TABLE nomination"
.Connection = SQLConnection
End With
Try
SQLConnection.Open()
SQLCommand.ExecuteNonQuery()
Catch ex As MySqlException
MsgBox(ex.Message.ToString)
Finally
SQLConnection.Close()
End Try
End If
End Sub
Private Sub truncate_table()
If MsgBox("Are you really sure you want to TRUNCATE this table?", MsgBoxStyle.Question + MsgBoxStyle.YesNo) = MsgBoxResult.Yes Then
Dim SQLCommand As New MySqlCommand
With SQLCommand
.CommandText = "TRUNCATE TABLE nomination"
.Connection = SQLConnection
End With
Try
SQLConnection.Open()
SQLCommand.ExecuteNonQuery()
Catch ex As MySqlException
MsgBox(ex.Message.ToString)
Finally
SQLConnection.Close()
End Try
End If
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
create_table()
End Sub
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
drop_table()
End Sub
Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
insert_row()
End Sub
Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click
update_row()
End Sub
Private Sub Button5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button5.Click
select_from()
End Sub
Private Sub Button6_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button6.Click
truncate_table()
End Sub
End Class
Here's the form I used, it needs Button1 - Button6, TextBox1 - TextBox5, ComboBox4 and a DataGridView control.
Hope this helps you out.