如何添加一列，通过在C＃中的DataTable数据库（MS接入）

如何数据库永久使用的DataTable添加一列，我希望这样的

 

   Projects.connection = new OleDbConnection(Projects.connectionstring);

            Projects.connection.Open();        

            Projects.da = new OleDbDataAdapter(Projects.cmdstring, Projects.connection);

            Projects.dt = new DataTable();

            Projects.da.Fill(Projects.dt);

            Projects.dt.Columns.Add("new column name");

            Projects.cmdb = new OleDbCommandBuilder(Projects.da);

 



                    Projects.dt.GetChanges();

 



 

                    if (Projects.dt.GetChanges() != null)

                    {

 

                        Projects.da.Update(Projects.dt);

                        Projects.connection.Close();

 

                    }

                    Projects.dt.AcceptChanges();