SQL and VISUAL BASIC 2008 Queries

Question

Hello guys,

How can I write a sql query that takes information from a database, and then put in the text in a label? I'm not really sure how to do this so please give me a good explanation! :)

Thanks,

Kevin

Answer 1

For using MySQL with .NET I'd recommend you this tutorial, and for your problem specially part 6, about reading the data with a MySQLDataReader.

An (almost working) sample by copy&paste from there with some changes:

Private Sub getData()
   Dim conn As New MySqlConnection
   Dim myCommand As New MySqlCommand
   Dim myReader As MySqlDataReader
   Dim SQL As String

   SQL = "SELECT LabelContent FROM myTable"

   conn.ConnectionString = myConnString ' your connection string here'

   Try
     conn.Open()

     Try
    myCommand.Connection = conn
    myCommand.CommandText = SQL

    myReader = myCommand.ExecuteReader

          ' loop through all records'
    While myReader.Read
     Dim myLabelValue as String
     myLabelValue = myReader.GetString(myReader.GetOrdinal("LabelContent"))

     ' ... do something with the value, e.g. assign to label '
    End While
     Catch myerror As MySqlException
    MsgBox("There was an error reading from the database: " & myerror.Message)
     End Try
   Catch myerror As MySqlException
   MessageBox.Show("Error connecting to the database: " & myerror.Message)
   Finally
   If conn.State <> ConnectionState.Closed Then conn.Close()
   End Try
End Sub

Answer 2

MSDN has lots of examples of getting data via ADO.NET. E.g. http://msdn.microsoft.com/library/dw70f090.

You will need to adjust the connection and command types (and the connection string) to be correct for My SQL. If you have ODBC drivers for My SQL then you can follow the ODBC example with just a change of connection string.