Since the enterprise environment changes from time to time, the conceptual schema will have to reflect these changes. This thesis presents a set of fundamental operations which are useful for constructing and modifying the conceptual schema to reflect the changes above, and discusses the consequences of these operations. We use the Entity-Category-Relationship(E-C-R) model, which enables us to capture more semantics of the real world, as a conceptual model for constructing conceptual schema. Also, we present a method for translating the E-C-R scheme into the relational scheme in the third normal form in which the semantics and the integrity constraints of conceptual schema are well preserved.
This method could serve as a guideline for developing the systematical relational database design tool which can be used for automatic translation of the E-C-R scheme into the relational scheme. Finally, a prototype relational database design tool is implemented in the C language under UNIX(4.2 BSD) system.
