A categorical entity-relationship model of databases

The major objective of the author is to develop a highly abstract model for databases: the categorical entity-relationship (CER) model. This model is based on a unified view of the entity-relationship and relational database models. Central to the CER model is the concept of an entity-relationship (ER) object. The concept of a key defines the identity of an ER-object. An ER-object with an atomic key represents a database entity; an ER-object with a composite key represents a database relationship. The concept of a schema represents the type of an ER-object. Operations are defined on ER-objects. The role is to define the structure of a database, to update a database, and to derive information from a database. This model provides a sufficiently rich basis for designing and implementing entity-relationship and relational databases as object-oriented systems