The nondeterministic or deterministic entity-relationship model of a database is formaRy defined as a user's view of that database in terms of a collection of time-varying relations: the regular or weak entity relations, or the regular or weak relationship relations. Both nondeterministic and deterministic entity-relationship models have the same strength to characterize information concerning entities and relationships which exist in our minds. An improved table form of the relations is introduced to provide a clear and concise user's view of databases. The basic concept of the entity-relationship approach to the logical database design is provided, and is used to derive 3NF relations. FinaUly, a method of representing physicaly these relations, which are generated by the use of the entity-relationship approach to the logical database design, is presented. Thus, the entity-relationship approach to the logical and physical database design can also be realized.