This paper discusses a stream of research which applies some classification principles to database design. We present a data model explicitly based on classification research. Subsequently, we examine implications of th'e model for flexibly handling diverse views of the class requirements for a domain, for developing methods and techniques to design databases, and for implementing data structures which support dynamic classification. The paper concludes by proposing that applying classification research to database research can lead to advances in the former, as well as in the latter. A widely used technique for data modeling, the Entity-Relationship (ER) model, uses diagrams to express data requirements in terms of classes (termed entity types in ER jargon), relationships among classes, and attributes, which jointly are referred to as a conceptual schema. Conceptual schema diagrams provide the basis for designing the files that will store the data. The primary implementation technologies for databases today are relational and object-orienteddatabase systems, both of which are also based on organizing data according to a fixed schema of classes. In a relational database system, each file (called a relation) is defined in terms of a numberoffields Data modeling and database design have emerged as a collection of techniques for determining, verifying, and codifying data requirements for various information systems applications or uses. One key element of data modeling is identifying the classes or categories of things about which data are to be kept, which attributes of those things must be kept track of, and what relationships exist among instances of different classes. For example, an application to maintain course registration records at a university might identify relevant classes of things such as students, instructors, sections, and rooms. Relevant attributes of might include name, address, date of birth, year, and major. Important relationships among classes might include: students enroll in'courses, insttuctors teach courses, and courses have multiple sections.