private void button1_Click(object sender, EventArgs e)
      {
connetionString = "Provider=MSDAORA;Data Source=orcl;Persist Security Info=True;User ID=system; password=system;";
            connection = new OleDbConnection(connetionString);
            Sql = "select * from system.prt_8";
            ds.Reset();
                connection.Open();
                oledbAdapter = new OleDbDataAdapter(Sql, connection);
                oledbAdapter.Fill(ds);
                
                dataGridView1.DataSource = ds.Tables[0];
       }