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Aditi Deductive Database System: Beta Release Announcement

The Aditi Deductive Database System is a multi-user deductive database
system being developed by the Machine Intelligence Project of the
University of Melbourne, Australia, located at the Collaborative
Information Technology Research Institute (CITRI), Melbourne,
Australia.

The system is now ready for beta-level testing, and we are looking for
sites to assist us in this. The system is currently available for SUN
SPARC-based machines running SunOS 4.1.2 or higher and Silicon
Graphics Power series multiprocessor machines running IRIX 4.0 or
higher.

If you would like to be one of these sites, send email to:

	 aditi@cs.mu.oz.au

We envisage the system could be used as a teaching aid, a research
tool or as an application development tool and we would like to have a
mixture of such sites to fully test the system. We therefore ask that
you outline briefly for what sort of purpose you would use the system.
Groups currently using Prolog and requiring better database support
may find Aditi quite useful in this regard.


A brief discussion of Aditi follows:

Aditi is a multi-user deductive database system.  It supports base
relations defined by facts (relations in the sense of relational
databases) and derived relations defined by rules that specify how to
compute new information from old information.  The old information can
be from derived relations as well as base relations; the rules of
derived relations may be recursive.  Both base relations and the rules
defining derived relations are stored on disk and are accessed as
required during query evaluation.  Users may ask queries on relations
without knowing whether they are base or derived.  This allows
seamless integration between rules and data.  There is no restriction
on the number of rules in the database and how they invoke each other.
This allows complex rule systems to be built up quickly from smaller
re-usable components.

The rules defining derived relations are expressed in a Prolog-like
language, which is also used for expressing queries.  Aditi supports
the full structured data capability of Prolog.  Base relations can
store arbitrarily nested terms, for example arbitrary length lists,
and rules can directly manipulate such terms.

Base relations contain variable sized records.  Base relations can be
indexed with B-trees or multi-level signature files (superimposed code
words) allowing multi-attribute indexing and querying, or they can be
stored as unindexed flat files.  Query evaluation makes use of
whatever indexing is available to ensure efficient computation of
answers.

Users can access the system through a Motif-based query and database
administration tool, or through a command line interface.  There is
also in interface that allows NU-Prolog programs to access Aditi in a
transparent manner. Deductive database support can thus be added to
existing Prolog applications with minimum change.

Relations and rules in external databases are shared among all
applications.  Updates (insertions and deletions) can be performed
through all Aditi's user interfaces.  Appropriate concurrency control
methods are employed to ensure that data is not corrupted through
simultaneous updates.  Proper transaction processing is not supported
in this release but is currently being implemented for the next
release.

The development of the Aditi system started in 1988 by Professor
Kotagiri Ramamohanarao, and many people have been involved in its
development, in particular Jayen Vaghani, Tim Leask, Peter Stuckey,
John Shepherd, Zoltan Somogyi, James Harland and David Kemp. The
support of Kim Marriott, David Keegel, and Warwick Harvey is also
acknowledged.


For those who are wondering, Aditi is the name of an Indian Goddess.

*	Jayen Vaghani                                                        *
*	Department of Computer Science                                       *
*	University of Melbourne, Australia                                   *
*	Ph: +61 3 282-2481   Email: jayen@cs.mu.oz.au                        *