private void Form1_Load(object sender, EventArgs e)
        {
 DataRelation relation = new DataRelation("klientsind_tren",
                dbAtletDataSet.Tables["klients"].Columns["id_klients"],
                dbAtletDataSet.Tables["ind_tren"].Columns["id_klients"]);
                dbAtletDataSet.Relations.Add(relation);

                klientsBindingSource.DataSource = dbAtletDataSet;
                klientsBindingSource.DataMember = "klients";
                
                indtrenBindingSource.DataSource = klientsBindingSource;
                indtrenBindingSource.DataMember = "klientsind_tren";
        }

dataGridView2.DataSource = dbAtletDataSet.ind_tren;
           ind_trenTableAdapter.Update(dbAtletDataSet);