This chapter introduces many of the concepts associated with CA IDMS databases. It describes how data in the database is organized, stored and inter-related and how that information is represented graphically through a data structure diagram.
It is important for navigational DML programmers to understand these concepts because, as discussed in the next chapter, the way in which data is organized affects the types of navigational DML commands that can be used to access it. Furthermore, the choice of which type of access technique is used can significantly impact an application's performance.
This section contains the following topics:
Types, Occurrences, and Relationships
Representing Relationships as Sets
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