The Applicability of Hypermedia Technology to Database Design
This work discusses an investigation into the applicability of hypermedia technology, in particular problem-resolution systems, to the conceptual modelling stage of the database design process. Conceptual modelling produces a representative abstraction (schema) of the data requirements of an organisation. Hypermedia is a form of information representation and management based on the principle of connecting nodes of self-contained chunks of information with links. It therefore seems suited to the representation and management of irregularly-structured design documents. Conceptual modelling comprises schema modelling and schema integration. The complexity of conducting large-scale conceptual modelling work can be reduced by developing individual schemas of subsets of an organisation's data requirements (schema modelling) and then amalgamating them (schema integration). Schema modelling involves identifying entities whose data is to be represented in a database along with their relationships. Schema modelling can exploit the modularity offered by hypermedia in representing these concepts. Inevitably, individual schemas may duplicate some data, leading to undesirable redundancy. Schema integration aims at producing a conceptual schema with no redundancy. This process requires detailed information, which is perspective-dependent and is often missing in the subschemas. Thus schema integration is necessarily a process of achieving semantic consensus. Achieving semantic consensus is necessarily a collaborative process which involves negotiation between the various stakeholders in the conceptual schema. The valuable information resulting from such negotiation is often lost because of lack of mechanisms to effectively capture such ill-structured information. The Issue-Based Information System (IBIS) [Rittel and Kunz 1970] provides a framework that supports and documents negotiation. A collaborative hypermedia-based IBIS environment for schema integration may reduce this problem. It is proposed that the main contributions to knowledge are: a.The construction of working prototypes that demonstrate many of the features of a possible infrastructure for collaborative conceptual modelling. b.The assessment of the usefulness of a collaborative schema integration tool in capturing integration rationale by consensus.
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