Because the number of implementation objects in a database is potentially very large, a CORBA server cannot keep in-memory ties to all the persistent implementation objects it touches during its execution. The last item above addresses the need of releasing p-ties\ from time to time. Each p-tie is instantiated with a ``net reference count'' of zero -- an initial reference count of one, plus a pending release call, to be performed by the ODA at the end of the operation. Unless the server code issues duplicate calls on them, p-ties have short lifetime: they exist while a request is being serviced. Whenever a discarded p-tie is needed again, an equivalent to it will be instantiated by an object activation upcall.