try
{
Transaction tx = odmg.newTransaction();
tx.begin();
Table_1Object table1Obj = new Table_1Object();
Table_2Object table2Obj = new Table_2Object();
table1Obj.setTable2Object(table2Obj);
db.makePersistent(table2Obj);
db.makePersistent(table1Obj);
tx.commit();
}