Как правильно выполнить команду SELECT и присвоить значение переменным

        'Выбираю значение из табл. Принтер
        Dim Connect1 As New OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & Path)
        zSQL1 = String.Format("SELECT PrintNum, PrintBrand FROM Printer WHERE KatrNum={0}", zKNum)
        Dim Command1 As New OleDb.OleDbCommand(zSQL1, Connect1)
        Connect1.Open()
        Dim dReader As OleDb.OleDbDataReader
        dReader = Command1.ExecuteReader(CommandBehavior.CloseConnection)
        While dReader.Read
            zPNum = dReader.GetValue(0)
            zBrand = dReader.GetValue(1)
        End While
        'Добавляю данные в таблицу Заявка
        Dim Connect As New OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & Path)
        zSQL = "INSERT INTO Zajavka(Data, KatrNum, PrintNum, PrintBrand, Kol_Str, Zapravka, Remont) VALUES(@p1, @p2, @p3, @p4, @p5, @p6, @p7)"
        Dim Command As New OleDb.OleDbCommand(zSQL, Connect)
        Command.Parameters.Add("@p1", OleDb.OleDbType.Date, 0).Value = zData
        Command.Parameters.Add("@p2", OleDb.OleDbType.BSTR, 0).Value = zKNum
        Command.Parameters.Add("@p3", OleDb.OleDbType.BSTR, 0).Value = zPNum
        Command.Parameters.Add("@p4", OleDb.OleDbType.BSTR, 0).Value = zBrand
        Command.Parameters.Add("@p5", OleDb.OleDbType.BSTR, 0).Value = zKolStr
        Command.Parameters.Add("@p6", OleDb.OleDbType.BSTR, 0).Value = zZapravka
        Command.Parameters.Add("@p7", OleDb.OleDbType.BSTR, 0).Value = zRemont
        Connect.Open()
        Command.ExecuteNonQuery()
        Connect.Close()
        Close()

        zSQL1 = String.Format("SELECT PrintNum, PrintBrand FROM Printer WHERE KatrNum={0}", zKNum)
        Dim Command1 As New OleDb.OleDbCommand(zSQL1, Connect1)
        Connect1.Open()
        Dim dReader As OleDb.OleDbDataReader
        dReader = Command1.ExecuteReader(CommandBehavior.CloseConnection)
        While dReader.Read
            zPNum = dReader.GetValue(0)
            zBrand = dReader.GetValue(1)
        End While

Dim SQL1 As New OleDb.OleDbCommand("SELECT PrintNum FROM Printer WHERE KatrNum=0", Connect1)
Dim SQL2 As New OleDb.OleDbCommand("SELECT PrintBrand FROM Printer WHERE KatrNum=0", Connect1)
Connect1.Open()
zPNum = SQL1.ExecuteScalar()
zBrand = SQL2.ExecuteScalar()
Connect1.Close

Dim SQL1 As New OleDb.OleDbCommand
Dim zPNum As Object ' или формат значения PrintNum в базе данных
zPNum = SQL1.ExecuteScalar()

Dim SQL1 As New OleDb.OleDbCommand("SELECT PrintNum FROM Printer WHERE KatrNum='" & zkNum & "'" , Connect1)

        Dim Connect1 As New OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & Path)
        MsgBox(zKNum)
        Dim SQL1 As New OleDb.OleDbCommand("SELECT PrintNum FROM Printer WHERE KatrNum='" & zKNum & "'", Connect1)
        Dim SQL2 As New OleDb.OleDbCommand("SELECT PrintBrand FROM Printer WHERE KatrNum='" & zKNum & "'", Connect1)
        Connect1.Open()
        zPNum = SQL1.ExecuteScalar()
        zBrand = SQL2.ExecuteScalar()
        Connect1.Close()