Posto il codice vb:

Dim objCommand As OleDbCommand = New OleDbCommand()

' Save the current record position...


' We must open the connection to the Microsoft Access database
objConnection.Open()

' Set the SqlCommand object properties...
objCommand.Connection = objConnection

' We set using standard SQL statement for inserting
' data in the database
objCommand.CommandText = "INSERT INTO Tabella " & _
"(codice, marca, descrizione, importo, fornitore) " & _
"VALUES(@codice,@marca,@descrizione, @importo, @fornitore);"

' We must to add parameters to the oledbCommand object
' Parameter for the FirstName column
objCommand.Parameters.AddWithValue("@codice", codice_a_barre.Text)
' Parameter for the LastName column
objCommand.Parameters.AddWithValue("@marca", marca.Text)
' Parameter for the Address column...
objCommand.Parameters.AddWithValue("@descrizione", descrizione.Text)
objCommand.Parameters.AddWithValue("@importo", Importo.Text)
objCommand.Parameters.AddWithValue("@fornitore", fornitore.SelectedValue)
' Execute the OleDBCommand object to insert the new data
Try
objCommand.ExecuteNonQuery()
Catch OleDbExceptionErr As OleDbException
MessageBox.Show(OleDbExceptionErr.Message)
End Try
' Close the connection...
objConnection.Close()
' Fill the dataset and bind the fields...
' Set the record position to the one that you saved...
' Show the current record position...
lblInformation.Text = "New customer added !!!"


objconnection è questa:
Dim objConnection As New OleDbConnection _
("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=prova.mdb;Persist Security Info=False")

Mi dice che il record è inserito conrrettamente ma quando apro il database, i campi nn vengono inseriti.. coma mai?