C#連接數據庫增刪改查代碼 SQL SERVER/ACCESS 通用類

using System.Data.OleDb;
using System.Data;

    public static class DataTools
    {
        private static OleDbConnection oleConn = new OleDbConnection("Provider=SQLOLEDB;Data Source=sz-lgp02;Initial Catalog=LGP;User ID=sa;Password=lgp123456");
//sql server database      
        public static string sourceName = "E:\\db\\####.accdb";
        public static OleDbConnection oleConn1 = new OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source= " + sourceName + ";");//access database

        public static int Insert(string sql)
        {
            int result = 0;
            try
            {
                oleConn.Open();
                OleDbCommand oleCommand = new OleDbCommand(sql, oleConn);
                result = oleCommand.ExecuteNonQuery();                
            }
            catch (Exception exception)
            {
                throw;
            }
            finally { oleConn.Close(); }
            return result;
        }

        public static DataTable Select(string sql)
        {
            DataTable tb = new DataTable();
            try
            {
                oleConn.Open();
                OleDbDataAdapter adapter = new OleDbDataAdapter(sql, oleConn);
                adapter.Fill(tb);                
            }
            catch (Exception exception)
            {
                string message = exception.Message;
            }
            finally { oleConn.Close(); }
            return tb;
        }

        /// <summary>
        /// 根據命令執行刪除數據
        /// </summary>
        /// <param name="sql"></param>
        /// <returns></returns>
        public static int Delete(string sql)
        {
            int ifExecute = 0;
            try
            {
                oleConn.Open();
                OleDbCommand comm = new OleDbCommand(sql);
                ifExecute = comm.ExecuteNonQuery();
            }
            finally
            {
                oleConn.Close();
            }
            return ifExecute;
        }
        /// <summary>
        /// 更新數據
        /// </summary>
        /// <param name="sql"></param>
        /// <returns></returns>
        public static int Update(string sql)
        {
            int ifExecute = 0;
            try
            {
                oleConn.Open();            
                OleDbCommand comm = new OleDbCommand(sql, oleConn);
                ifExecute = comm.ExecuteNonQuery();
            }
            finally
            {
                oleConn.Close();
            }
            return ifExecute;
        }

        /// <summary>
        /// 執行sql返回對象
        /// </summary>
        /// <param name="sql"></param>
        /// <returns></returns>
        public static object ExecuteSingle(string sql)
        {
            object obj = null;
            try
            {
                oleConn.Open();
                OleDbCommand comm = new OleDbCommand(sql, oleConn);
                obj = comm.ExecuteScalar();
            }
            finally
            {
                oleConn.Close();
            }
            return obj;
        }
    }