Question

VB.NET, Winforms Application with MySQL. In my app I have added the ability to Update it through the use of mail attachments because of limitations of Funds and Connection reliability. Everything works good. Well in the Apps form load even I have it check for the existence of a file. If it exists there are changes to be made to the database. So the below Sub is called and the contents of that file are read in to an arrayList… I am getting the “CommandText property has not been properly Initialized” error when the app starts from outside VS.

 Private Sub sqlUpdate(ByVal sqlScriptName As String)
    Dim D As Boolean = BackupDatabase("C:\xxxxxxxx\temp.sql")

    Dim objReader As New StreamReader(sqlScriptName)
    Dim sLine As String = ""
    Dim arrText As New ArrayList()
    Do
        sLine = objReader.ReadLine()
        If Not sLine Is Nothing Then
            arrText.Add(sLine)
        End If
    Loop Until sLine Is Nothing
    objReader.Close()

    For Each sLine In arrText
        Dim conn As New MySqlConnection
        Dim myCommand As New MySqlCommand
        Dim connString As String = My.Settings.storageConnectionString
        conn.ConnectionString = connString
        myCommand.Connection = conn
        myCommand.CommandText = String.Empty
        Try
            myCommand.CommandText = sLine
            conn.Open()
            myCommand.ExecuteNonQuery()
        Catch myerror As MySqlException
            'MsgBox("There was an error updating the database: " & myerror.Message + vbNewLine + "PLEASE CONTACT THE DEVELOPER IMMEDIATELY")
        End Try

    Next

    Return

End Sub

Not sure where the Problem is comming from and have followed the execution all the way down… The sList contains Valid MYSQL commands that look like this:

  ALTER TABLE `storage`.`property_info` ADD COLUMN `pfam_pName` CHAR(200) NULL  AFTER `pfam_Phone` ;

Any ideas that could send me in the right direction with this???

Answer 1

I found no error on your code but I suspect that there are empty lines in your script thus allowing it to pass empty string on your command text. Please do modify the reading of file into this,

Do
    sLine = objReader.ReadLine()
    If (Not sLine Is Nothing) Then
        If sLine.Trim().Length <> 0 Then      ' this will not add empty line '
           arrText.Add(sLine)
        End If
    End If
Loop Until sLine Is Nothing

or

For Each sLine In arrText 
    If sLine.Trim().Length = 0 Then Continue For   ' skips for empty line '

    Try 
        myCommand.CommandText = sLine 
        myCommand.ExecuteNonQuery() 
    Catch myerror As MySqlException 
        MsgBox("There was an error updating the database: " & _
                myerror.Message & vbNewLine & _
                "PLEASE CONTACT THE DEVELOPER IMMEDIATELY") 
    End Try 
Next