Dirk,
To relate objects to calendar items we just need a mapping table, or a related_object_id column in acs_events. If you want more than one object per calendar item, then you need a mapping table obviosuly. One option is to define a new relationship type and use acs_rels. Using acs_rels, to store user-mapped objects could allow a consisten interface in some future openacs based system such as knowledge management. A mapping table is easier to code.
Jade,
The service contract was to allow other pakcages besides calendar to provide the same calendar interface. This way you could actually store all your calendar items in a calendar server, but the packages that use calendar would not know the difference. To make this work, a tcl api would need to be defined to calendar, and every package that accessed calendar would use the tcl-api instead of accessing the database directly. Then if the calendar objects were stored outside the openacs database, the use would be transparent to the packages. This is not necessary to map objects to calendar items.
