Component-Driven Engineering of Database Applications

Though it is commonly agreed that the design of large database schemata requires group e#ort, database design from component subschemata has not been investigated thoroughly. In this paper we investigate snowflake-like subschemata of database schemata expressed in the Higher-order Entity-Relationship Model (HERM). These subschemata are almost hierarchical in the sense that they may contain cycles in the schema, but not in the instances. We show that each HERM schema can be decomposed into such subschemata using a small set of composition constructors. We then describe how the composition of components can be seen as a database design primitive leading to component-driven database design and re-design pragmatics