Overview

ICOM is an advanced CASE tool, which allows the user to design multiple extended Entity-Relationship (EER) diagrams. Each diagram can be organized into several schemas, with the possibility to include inter- and intra-schema constraints. Complete logical reasoning is employed by the tool to verify the specification, infer implicit facts, devise stricter constraints, and manifest any inconsistency. ICOM is fully integrated with a very powerful description logic reasoning server which acts as a background inference engine.

The conceptual modelling language supported by ICOM can express:

• the standard Entity-Relationship data model, enriched with IsA links (i.e., inclusion dependencies), disjoint and covering constraints, full cardinality constraints, and definitions attached to entities and relations by means of view expressions over other entities and relationships in the schema;
• rich class of (inter-schema) integrity constraints, as inclusion and equivalence dependencies between view expressions involving entities and relationships possibly belonging to different schemas.

The tool supports multiple schemas with inter-schema constraints but it turned out to be extremely useful also in supporting the conceptual modelling of ``classical'' databases involving a single rich schema with integrity constraints, and in designing ontologies for various purposes.

ICOM reasons with (multiple) diagrams by encoding them in a single description logic knowledge base, and shows the result of any deductions such as inferred links, new stricter constraints, and inconsistent entities or relationships. Theoretical results guarantee the correctness and the completeness of the reasoning process. To the best of our knowledge, this is the first implemented tool for EER conceptual modelling with a provably complete inference mechanism for consistency checking and for deduction - i.e., derivation of implied links and constraints in the schema. Completeness of reasoning means in this context that no valid deduction is left out by the inference engine. This of course holds for the full data model employed by ICOM, which is much richer than EER. The system employs the DLR/SHIQ description logic to encode the schemas and to express the views and the constraints.

The tool allows for the creation, the editing, the managing, and the storing of several interconnected conceptual schemas, with a user friendly graphical interface. The ICOM tool is written in standard Java 5.0, and it is being used on Linux, Mac, and Windows machines. ICOM communicates via the DIG protocol with a description logic server. Experiments with ICOM show that it is able to handle very large schemas, such as the integrated Conceptual Data Warehouse Model of a national European telecom company. ICOM provides an interface for importing and exporting schemas in UML-XMI class diagrams format. An new version of ICOM handling UML class diagrams is under development.

The intention behind ICOM is to provide a simple, freeware conceptual modelling tool that demonstrates the use of, and stimulates interest in, the novel and powerful knowledge representation based technologies for database and ontology design. In particular, we are interested to cooperate with researchers and companies considering the opportunity to incorporate these technologies in their tools.

For more details about the theory behind ICOM, and in particular about the proper use of the DLR view language please refer to:

• Enrico Franconi and Gary Ng (2000). The ICOM Tool for Intelligent Conceptual Modelling. 7th Intl. Workshop on Knowledge Representation meets Databases (KRDB'00), Berlin, Germany, August 2000.
• Diego Calvanese, Giuseppe De Giacomo, Maurizio Lenzerini, Daniele Nardi, and Riccardo Rosati (1998). Description Logic Framework for Information Integration. In Proc. of the 6th Int. Conf. on the Principles of Knowledge Representation and Reasoning (KR'98). 1998.
• Pablo Fillottrani, Enrico Franconi, Sergio Tessaris (2006). The New ICOM Ontology Editor. 2006 International Workshop on Description Logics, Lake District, United Kingdom. May 2006.

At the ICOM home page http://www.inf.unibz.it/~franconi/icom/ you can find a detailed on line tutorial on ICOM.