What if I define 100 pointers and assign each one of them everytime to the same client. The client registers the building in the database and assigns ID xxx. Now if I want to send to that client I use the ID for playerxxx pointer and the building stays independant , created by the server because of the database update. How does it look now,possible?

Extensive Multiplayer tutorial:
http://mesetts.com/index.php?page=201