Ode
An
Object-Oriented Database from
AT&T which extends
C++ and supports fast queries, complex application modelling and
multimedia.
Ode uses one integrated data model (
C++ classes) for both database and general purpose manipulation.
An Ode database is a collection of
persistent objects.
It is defined, queried and manipulated using the language O++.
O++ programs can be compiled with C++ programs, thus allowing the use of existing C++ code.
O++ provides facilities for specifying transactions, creating and manipulating persistent objects, querying the database and creating and manipulating versions.
The Ode object database provides four object compatible mechanisms for manipulating and querying the database.
As well as O++ there are OdeView - an
X Window System interface; OdeFS (a file system interface allowing objects to be treated and manipulated like normal Unix files); and CQL++, a
C++ variant of
SQL for easing the transition from
relational databases to OODBs such as Ode.
Ode supports large objects (critical for
multimedia applications).
Ode tracks the relationship between versions of objects and provides facilities for accessing different versions.
Transactions can be specified as read-only; such transactions are faster because they are not logged and they are less likely to
deadlock.
'Hypothetical' transactions allow users to pose "what-if" scenarios (as with
spreadsheets).
EOS, the storage engine of Ode, is based on a client-server architecture.
EOS supports
concurrency based on multi-granularity two-version two-phase locking; it allows many readers and one writer to access the same item simultaneously.
Standard two-phase locking is also available. Ode supports both a
client-server mode for multiple users with concurrent access and a single user mode giving improved performance.
Ode 3.0 is currently being used as the
multimedia database engine for
AT&T's Interactive TV project.
Ode 2.0 has also been distributed to more than 80 sites within AT&T and more than 340 universities.
Ode is available free to universities under a non-disclosure agreement.
The current version, 3.0, is available only for
Sun SPARCstations running
SunOS 4.1.3 and
Solaris 2.3.
Ode is being ported to
Microsoft Windows NT,
Windows 95 and
SGI platforms.
E-mail: Narain Gehani <
[email protected]>.
