Comments on: The VB.NET-MySQL Tutorial – Part 5

By: Bongs

Bongs — Mon, 07 Jun 2010 19:27:33 +0000

I am connected to MySQL database using localhost, I keep getting an error that says CONNECTION MUST BE VALID AND OPEN when I am trying to add a new record. I am using INSERT INTO statement. I need help. The exception is on the Executenonquery statement, here is the code:

Private Sub btnAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAdd.Click
Dim ConnStr As String = “server=localhost;user id=bongani;Password=bongs;persist security info=True;database=world”
Dim connection As New MySqlConnection(ConnStr)
connection.Open()
MyCommand = New MySqlCommand(“INSERT INTO pals values (‘” & txtName.Text & “‘, ‘” & txtSur.Text & “‘ ,’” & txtTel.Text & “‘)”)
If connection.State = ConnectionState.Open Then
MsgBox(“Connection is open”)
MyCommand.ExecuteNonQuery()
Else
MsgBox(“Connection is closed”)
End If

myData = New DataSet
myAdapter.Fill(myData, “pals”)
myAdapter.Update(myData, “pals”)
End Sub

By: methodman3130

methodman3130 — Thu, 13 May 2010 23:34:16 +0000

HOW TO DO CRYSTAL REPORTS WITH VB.NET AND MYSQL USING XML DATA? PLEASE HELP

By: Nokia6230ivn

Nokia6230ivn — Tue, 27 Apr 2010 14:54:27 +0000

Hi,

I have 2 matters in this lession.

1. I connected to my localhost many times and loading database is ok. But if I change it to my host, it has an error at section “MyAdapt.Fill(myDataTable)”.

2. If I connect to my database by localhost, “Refresh” button working very good, all chages of database update immediately (even frmMain had time control). But when the timer control working (automatic), it has an error: “Error connecting to the database: Access denied for user “@’localhost’ (using password: NO)

Please tell me how to correct these errors???

By: Ethel Hupp

Ethel Hupp — Tue, 06 Apr 2010 14:54:27 +0000

Try & Preserve your iPad for Free! -> http://bit.ly/cFBuis

By: B. Balamanigandan

B. Balamanigandan — Mon, 30 Nov 2009 08:18:11 +0000

How can i connect vb.net desktop application with remote mysql server?????????????????

By: Rhine

Rhine — Mon, 30 Nov 2009 06:51:58 +0000

I will try to do this but the demand now is Java. Is it possible to work if my knowledge is only VB

By: Charlie Childs

Charlie Childs — Thu, 05 Nov 2009 12:09:29 +0000

Alfredo and Ferando – just remembered that it also says that if the connection is left open, the database may be left open when the user thinks they have finished with it and closed it.

By: Charlie Childs

Charlie Childs — Thu, 05 Nov 2009 12:01:05 +0000

Alfredo and Fernando,

I am a beginner but have read this tutorial quite a lot and I think I have read two things that may be of interest to you:

1) Somewhere in this tutorial it sates that it is best practice to close connections as soon as they are finished with in order to save resourses.

2)I think I have read that the closing of the connection is used to trigger something. If I am right about that I think I remember it being in a TRY CATCH block but I cannot be certain.

I think that you will probably find a more definate answer to your question by reading through lesson 3 or 4.

Might you know of any reason that may be causing my form to overwrite existing rows rather than provide a new row.

Good luck

By: Fernando

Fernando — Wed, 04 Nov 2009 07:51:50 +0000

HI,

I’ve the same doubt as Alfredo Garza. Please, anyone ?

By: Alfredo Garza

Alfredo Garza — Fri, 23 Oct 2009 22:06:04 +0000

Hi,

I noticed that all of the connections to the database are open and closed right after finishing the data access. Is there any reason why not to leave the connection open until the aplication exits.