DataSet ds1 = new DataSet();

            DataTable t1 = new DataTable();
            DataTable t2 = new DataTable();

            DataColumn id1 = new DataColumn("id", typeof(int));
            id1.AutoIncrement = true;
            id1.AutoIncrementSeed = - 1 ;
            id1.AutoIncrementStep = - 1 ;
            id1.Unique = true;

            DataColumn id2 = new DataColumn("id", typeof(int));
            id2.AutoIncrement = true;
            id2.AutoIncrementSeed = - 1 ;
            id2.AutoIncrementStep = - 1 ;
            id2.Unique = true;

            t1.Columns.Add(id1);
            t1.PrimaryKey = new DataColumn[] { id1 };

            t2.Columns.Add(id2);
            t2.PrimaryKey = new DataColumn[] { id2 };
            t2.Columns.Add("lnk", typeof(int));

            ds1.Tables.Add(t1);
            ds1.Tables.Add(t2);
            ds1.Relations.Add(new DataRelation("rel", id1, t2.Columns["lnk"]));
            ds1.Relations[ 0 ].ChildKeyConstraint.UpdateRule = Rule.Cascade;
            ds1.Relations[ 0 ].ChildKeyConstraint.DeleteRule = Rule.Cascade;

            DataRow r;

            r = t1.NewRow();
            t1.Rows.Add(r);
            int FK = (int)r[id1];

            r = t2.NewRow();
            r["lnk"] = FK;
            t2.Rows.Add(r);

            t1.Rows.RemoveAt( 0 );

            ds.Table1Row r1 = ds.Table1.NewTable1Row();
            ds.Table1.AddTable1Row(r1);
            int FK = r1.id;

            ds.Table2Row r2 = ds.Table2.NewTable2Row();
            r2.lnk =  80 ;
            ds.Table2.AddTable2Row(r2);