Help connecting to MySQL with .NET Plz :D

Hi.. I am trying to make a very simple program that connects to a MySQL database using VB.NET. My program only has one form and one label. I setup my MySQL database to have a table and one field (a VARCHAR) called "Tab1". I manually inserted the value "CLOSED" into the Tab1 field using PHPMyAdmin. I want my program to change the value of the field to OPEN/CLOSED and I also want the label text on my form to change too when it's clicked.

So far, I've added the MySQL.data reference to my project and added:

Code:

---

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

---

To the General_Declarations

Also I declared a global variable containing a MySQL Connection:

Code:

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Public Class Form1

    Dim conn As New MySqlConnection

---

Here is my function that connects to MySQL:

Code:

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Private Function Connect(ByVal server As String, ByRef user As String, ByRef password As String, ByRef database As String)
        ' Connection string with MySQL Info
        conn.ConnectionString = "server=" + server + ";" _
        & "user id=" + user + ";" _
        & "password=" + password + ";" _
        & "database=" + database + ";"
        Try
            conn.Open()
            Return True
        Catch ex As MySqlException
            Return MsgBox(ex.Message)
        End Try
    End Function

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I made the program connect to MySQL on Form_Load like this:

Code:

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Connect("db4free.net", "boomun", "*******", "boomdb")

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And it connects fine but here is where I have the trouble.... I want the field to change from CLOSED to OPEN when I click Label1. It does, but it doesn't change back on the second click. Somehow I need a working code to Update the Tab1 field in my table.

Here is what I have so far:

Code:

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Private Sub Label1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Label1.Click
        Dim myCommand As New MySqlCommand
        Dim myAdapter As New MySqlDataAdapter
        Dim myData As MySqlDataReader
        Dim SQL As String

        SQL = "SELECT * FROM `boomtable` WHERE `Tab1` = 'CLOSED'"

        myCommand.Connection = conn
        myCommand.CommandText = SQL
        myAdapter.SelectCommand = myCommand
        Try
            myData = myCommand.ExecuteReader()
            myData.Read()
            If myData.HasRows = 0 Then
                Label1.Text = "CLOSED"
                SQL = " UPDATE boomtable SET Tab1 = 'CLOSED' WHERE Tab1 = 'OPEN' "
                SQL.ExecuteNonQuery()
                myData.Close()
            Else
                Label1.Text = "OPEN"
                SQL = " UPDATE boomtable SET Tab1 = 'OPEN' WHERE Tab1 = 'CLOSED' "
                SQL.ExecuteNonQuery()
                myData.Close()
            End If
        Catch ex As MySqlException
            MsgBox(ex.Message)
        End Try

    End Sub

---

VB gives me an error and highlights SQL.ExecuteNonQuery() and the error message is 'ExecuteNonQuery' is not a member of 'String'. Can anyone help???! Thanks



Here is the entire code of the project all together:

Code:

---

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

Public Class Form1

    Dim conn As New MySqlConnection

    Private Function Connect(ByVal server As String, ByRef user As String, ByRef password As String, ByRef database As String)
        ' Connection string with MySQL Info
        conn.ConnectionString = "server=" + server + ";" _
        & "user id=" + user + ";" _
        & "password=" + password + ";" _
        & "database=" + database + ";"
        Try
            conn.Open()
            Return True
        Catch ex As MySqlException
            Return MsgBox(ex.Message)
        End Try
    End Function

    Private Sub Label1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Label1.Click
        Dim myCommand As New MySqlCommand
        Dim myAdapter As New MySqlDataAdapter
        Dim myData As MySqlDataReader
        Dim SQL As String

        SQL = "SELECT * FROM `boomtable` WHERE `Tab1` = 'CLOSED'"

        myCommand.Connection = conn
        myCommand.CommandText = SQL
        myAdapter.SelectCommand = myCommand
        Try
            myData = myCommand.ExecuteReader()
            myData.Read()
            If myData.HasRows = 0 Then
                Label1.Text = "CLOSED"
                SQL = " UPDATE boomtable SET Tab1 = 'CLOSED' WHERE Tab1 = 'OPEN' "
                SQL.ExecuteNonQuery()
                myData.Close()
            Else
                Label1.Text = "OPEN"
                SQL = " UPDATE boomtable SET Tab1 = 'OPEN' WHERE Tab1 = 'CLOSED' "
                SQL.ExecuteNonQuery()
                myData.Close()
            End If
        Catch ex As MySqlException
            MsgBox(ex.Message)
        End Try

    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Connect("db4free.net", "boomun", "boom123", "boomdb")
    End Sub

End Class

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Hi.. Welcome to the forums...:wave:

You have declared SQL as a String and in the code, you are doing this:

Code:

---

SQL = " UPDATE boomtable SET Tab1 = 'OPEN' WHERE Tab1 = 'CLOSED' "
                SQL.ExecuteNonQuery()

---

where, the second line is invalid. Because, SQL is not a MySqlCommand object !. You've declared it as a String !

:wave:

Quote:

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Originally Posted by akhileshbc

Hi.. Welcome to the forums...:wave:

You have declared SQL as a String and in the code, you are doing this:

Code:

---

SQL = " UPDATE boomtable SET Tab1 = 'OPEN' WHERE Tab1 = 'CLOSED' "
                SQL.ExecuteNonQuery()

---

where, the second line is invalid. Because, SQL is not a MySqlCommand object !. You've declared it as a String !

:wave:

---

Any suggestions of how it should look instead? :blush::blush::blush:

Use a MySqlCommand object and with the SQL query, call the ExecuteNonQuery() method.

For example:

Code:

---

SQL = " UPDATE boomtable SET Tab1 = 'CLOSED' WHERE Tab1 = 'OPEN' "
myCommand.CommandText = SQL
myCommand.ExecuteNonQuery()

---

:wave:

Thank you... It executes fine but I get a mysql error when clicking the label.. "There is already an open DataReader associated with this connection that must be closed first"

hmm... Try adding this line before that:

Code:

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myAdapter.Close

---

:wave:

When I add it I get an error 'Close' is not a member of 'MySql.Data.MySqlClient.MySqlDataAdapter'.

Sorry. Try this:

Code:

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myAdapter.Dispose

---

:wave:

The error:

Quote:

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Originally Posted by BooMGiRL

"There is already an open DataReader associated with this connection that must be closed first"

---

Is telling you you have an open Reader. You opened a reader without closing it. check you code and close the open reader. You can not open a new one without first closing the prior open one.