If you review the OO modeling hierarchy (figure 7-11) of chapter 7, you will notice that the left hand side is characterized by the term object structure analysis (OSA). This chapter focuses on OSA, or more precisely, object structure design. In this chapter, we shall relax any distinction between database design and object structure design, for the following reason: As established in the previous chapter, irrespective of the software engineering paradigm employed, data (object) structure design is of paramount importance. By way of observation, most software engineering environments embrace the idea of a relational database, upon which an OO user interface is superimposed. This chapter presumes that convention, and provides you an overview of the database design experience. For a more comprehensive coverage of database systems, please refer to the recommended readings.