DAO objects and collections provide a framework for using code to create and manipulate components of your database system. Objects and collections have properties that describe the characteristics of database components and methods that you use to manipulate them. Together these objects and collections form a hierarchical model of your database structure, which you can control programmatically.

Objects and collections provide different types of containment relations: Objects contain zero or more collections, all of different types; and collections contain zero or more objects, all of the same type. Although objects and collections are similar entities, the distinction differentiates the two types of relations.

In the following table, the type of collection in the first column contains the type of object in the second column. The third column describes what each type of object represents.