A Methodology for Structural Conflict Resolution in the Integration of Entity-Relationship Schemas

Abstract.

The integration ofinf ormation systems is becoming increasingly important. A common requirement in distributed data-intensive applications, such as data warehousing and data mining, is that the various databases involved be joined in a process called schema integration. The entity-relationship (ER) model or a variant of the ER model is often used as the common data model. To aid the schema conforming, merging and restructuring phases of the integration process, various transformations have been defined to map between various equivalent ER representations. In this paper, we describe a different approach to integrate ER schemas. We focus on the resolution of structural conflicts, that is, when related real-world concepts are modeled using different constructs in different schemas. Unlike previous work, our approach proposes to resolve the structural conflict between an entity type in one schema and an attribute in another schema and show that the other structural conflicts are automatically resolved. This reduces the manual effort required in integration. We give a detailed algorithm to transform an attribute in one schema into an equivalent entity type in another schema without any loss of semantics, that is, our transformation is both information preserving and constraint preserving.