C# MSSQL数据库类

嘿嘿，今晚无聊写了个MSSQL操作类，算是C#征途的一个起步，博客园的各位朋友尽量拍砖！我的进步靠大家，希望大家不吝赐教！！

 1     class MsSql
 2     {
 3         private string connectString;
 4 
 5         public MsSql(string connString)
 6         {
 7             connectString = connString;   
 8         }
 9 
         /// <summary>
         /// 查询数据库，并返回DataSet集
         /// </summary>
         /// <param name="cmdString">查询语句</param>
         /// <returns>返回DataSet</returns>
         public DataSet GetDataSet(string cmdString)
         {
             SqlConnection sqlConn = new SqlConnection(connectString);
 
             SqlDataAdapter da = new SqlDataAdapter(cmdString, sqlConn);
             DataSet ds = new DataSet();
             try
             {
                 sqlConn.Open();
                 
                 da.Fill(ds);
                 //if (ds != null || ds.Tables.Count > 0)
             }
             catch (SqlException sqlex)
             {
                 Console.WriteLine(sqlex.Message);
             }
             sqlConn.Close();
             return ds;
         }
 
         /// <summary>
         /// 取得表
         /// </summary>
         /// <param name="cmdString">查询字符串</param>
         /// <returns>DataTable</returns>
         public DataTable GetDataTable(string cmdString)
         {
             SqlConnection sqlConn = new SqlConnection(connectString);
 
             SqlDataAdapter da = new SqlDataAdapter(cmdString, sqlConn);
             DataSet ds = new DataSet();
             try
             {
                 sqlConn.Open();
                 da.Fill(ds);
             }
             catch (SqlException sqlex)
             {
                 Console.WriteLine(sqlex.Message);
             }
             DataTable MyDataTable = ds.Tables[0];
             sqlConn.Close();
             return MyDataTable;
         }
 
         /// <summary>
         /// 执行sql语句
         /// </summary>
         /// <param name="cmdString">查询，更新，删除语句</param>
         /// <returns>成功返回true,失败返回false</returns>
         public bool ExecuteQuery(string cmdString)
         {
             SqlConnection conn = new SqlConnection(connectString);
 
             SqlCommand cmd = new SqlCommand(cmdString,conn);
             cmd.CommandText = cmdString;
             try
             {
                 conn.Open();
 
                 if (cmd.ExecuteNonQuery() > 0)
                 {
                     conn.Close();
                     return true;
                 }
                 else
                 {
                     return false;
                 }
             }
             catch (SqlException Sqlex)
             {
                 Console.WriteLine(Sqlex.Message);
                 return false;
             }

91         }