Objectivity specifics
- virtually unlimited number of DB files
- one or more containers in a given file.
- Relationships (later) can span the whole Federation.
- Relationships can span the whole Federation (I repeat this because it’s important).
So we have The Big One Federation in PHENIX. All HV, run info, run config, Calib, Geometry, whatnot, will be separate databases (files) but part of that same federation.
With the 2GB file size limit, some of the above in itself will be more than one database file.
Containers aid to physically place stuff that belongs together close together for the DB system, and look like subdirectories to the user.
(For development, we have a staggered line of test federations, which you must test your new class with).