/// <summary>
        /// import from sheet TypPZS
        /// </summary>
        /// <param name="excel_con"></param>
        private void ImportTypPZS(OleDbConnection excel_con)
        {
            DataTable dtExcelData = new DataTable();

            //[OPTIONAL]: It is recommended as otherwise the data will be considered as String by default.
            dtExcelData.Columns.AddRange(new DataColumn[5] {
                new DataColumn("Id", typeof(int)),
                new DataColumn("Kod", typeof(string)),
                new DataColumn("Nazev", typeof(string)),
                new DataColumn("DatumOd", typeof(DateTime)),
                new DataColumn("DatumDo", typeof(DateTime))
            });

            using (OleDbDataAdapter oda = new OleDbDataAdapter("SELECT * FROM [TypPZS$]", excel_con))
            {
                oda.Fill(dtExcelData);

                foreach (DataRow row in dtExcelData.Rows)
                {
                    _dataConnector.CreateTypPZS((string)row["Kod"], (string)row["Nazev"], (DateTime)row["DatumOd"], row.IsNull("DatumDo") ? null : (DateTime?)row["DatumDo"]);
                }
            }
        }