EXTENDING THE ENTITY-RELATIONSHIP MODEL FOR A HIGH-LEVEL, THEORY-BASED DATABASE DESIGN

Database design methodologies should facilitate database modeling, effectively support database processing and transform a conceptual schema of the database to a high-performance database schema in the model of the corresponding DBMS. Since the late 1970's, various methodologies for database design have been introduced. Most of them, however, are dependent on the knowledge, comprehension and experience of the database analyst and their knowledge in normalization theory. The proposed methodology does not require the user to understand the theory, the implementational restrictions and the programming problems in order to design a database scheme. A novice designer can create a database design successfully using this method. The Entity-Relationship Model is extended to the Higher-order Entity-Relationship Model (HERM) by relationships of higher degrees and relationships of relationships. This model is used for a high-level database design system DBDB (DataBase Design by Beta). The HERM supports an efficient translation to nested relational, relational, network and hierarchical schemes. The model has the expressive power of semantic models and possesses the simplicity of the entity-relationship model.