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The Declare Developers' Toolkit DDK and
the Deductive Database System DDBase

by Dietmar Seipel

Declare is a collection of libraries for declarative programming including features from

• data and knowledge engineering,
• databases (relational, XML, deductive), ontologies, and
• non-monotonic reasoning

developed in SWI-Prolog. The deductive database system DDBase is part of the Declare.

Declare

The Declare project started with building a system DisLog for non-monotonic reasoning in disjunctive deductive databases. In the meantime a variety of additional packages for different purposes has been implemented:

• a deductive database system DDBase
• management and querying of XML-data
• reasoning about programs in knowledge and software engineering
• artificial intelligence in various fields (including medicine, games, etc.)
• management of data in bio-informatics
• management, analysis, and visualisation of data from sports and stock information

Most of the packages are equipped with graphical user interfaces, that have been developed in the object-oriented extension XPCE of SWI-Prolog.

Declare can be obtained as a tgz-archive (of about 9 MB) at

• https://www1.pub.informatik.uni-wuerzburg.de/databases/Declare.tgz

DDBase

DDBase uses the extension Datalogs of Datalog with function symbols. Rule bodies can contain embedded Prolog calls and default negation.

It is possible to have bottom-up and top-down evaluation in one system. Datalogs can evaluate logic programs with Prolog syntax (extended Datalog programs) in a bottom-up style; it is designed to evaluate embedded Prolog calls in a top-down manner.

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