DB연결객체과 Excel Access 연결객체를 만들어주는 놈을 만들었다. 

    /// <summary>
    /// 연결 문자열 팩토리.
    /// </summary>
    public static class OleDbConnetionFactory
    {

        /*
            Provider (OLE DB only) 
            Access : Microsoft.JET.OLEDB.4.0 
            Oracle - MSDAORA 
            MS SQL - SQLOLEDB 
            Data Source(server) :  데이터베이스 위치 (Domain or IPAddress) 
            Initial Catalog (database): 데이터 베이스 이름 
            User ID/Password : 인증 정보  
         */
        /// <summary>
        /// MS-SQL 데이타 베이스 연결 문자열.
        /// </summary>
        /// <returns> 연결 문자열 </returns>
        public static string MSSQLConnectionString()
        {
            Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
            AppSettingsSection appSetting = (AppSettingsSection)config.GetSection("AppSettings");

            OleDbConnectionStringBuilder oleCon = new OleDbConnectionStringBuilder();
            oleCon.Add("Provider", "SQLOLEDB");
            oleCon.Add("Data Source", string.Format("{0}", "서버명"));
            oleCon.Add("UID", "아이디");
            oleCon.Add("PWD", "패스워드");
            oleCon.Add("Database", "DB명");
            return oleCon.ConnectionString;
        }


        /// <summary>
        /// 엑셀-> 읽기, 쓰기관련 플래그 셋팅
        /// </summary>
        public enum Excel_Imex
        {
            /// <summary>
            /// 읽기 적용
            /// </summary>
            Read = 1,
            /// <summary>
            /// 쓰기 적용.
            /// </summary>
            Write = 0
        }
        /// <summary>
        /// 엑세스(Excel) 데이타 베이스 연결 문자열
        /// </summary>
        /// <param name="ExcelFilePath"></param>
        /// <param name="imex"></param>
        /// <returns> 연결 문자열 </returns>
        public static string ExcelConnectionString(string ExcelFilePath, Excel_Imex imex)
        {
            OleDbConnectionStringBuilder oleCon = new OleDbConnectionStringBuilder();
            oleCon.Add("Provider", "Microsoft.Jet.OLEDB.4.0");
            oleCon.Add("Data Source", string.Format("{0}", ExcelFilePath));
            oleCon.Add("Extended Properties", string.Format("Excel 8.0;imex={0};HDR=Yes", (int)imex));
            return oleCon.ConnectionString;
        }
    }