o2com 11

11 Mandatory features for a DBMS

Being a database system should mean providing a few mandatory and somewhat
obvious features:

- Persistence: in O2, persistence is defined by reachability, supporting the
  goal of making it orthogonal with the typing.
- Secondary Storage Management: support for large amounts of data
- Recovery from hardware or external failure
- Concurrency of access
- Ad-hoc query facility

Issues not listed here are felt either optional or controversial. Among
these issues labeled as controversial, two are not otherwise dealt with in
the book:

- Database administration: on-line support, e.g. backup...
- Integrity constraints (e.g. not in ObjectStore)