User-Defined Queries

Abstract

This chapter describes object-based user-defined queries in Oracle™. The queries will vary based on the hierarchy of the object model. We will show different categories of queries along the object-oriented relationships of inheritance, association, and aggregation. These queries can be performed as ad hoc queries or implemented as methods. User-defined methods are methods whereby users define algorithms or the processes to be carried out by the methods. Since these methods involve operations specified by the users, they are called user-defined methods. As an example, we will use the case study of the authorship of the course manual in Chapter III as a working example for this chapter. Some queries discussed here are based on the DDL specified in Figure 3.36.