SDO_DAS_Relational limitations

Hi, I'm looking into the SDO implementations and walked into the limitations very quickly. Limitations: - No composite key possible - Only one Foreign key per table - No way of setting up a many to many relationschip My models violates mostly and most likely all of this limitations. So I ask myself. Is it usefull or don't I understand the stratergy? what to do with the many to many relationships, the composite keys and multiple foreignkeys per table ??? kind regards Jeroen Olthof