|Libraries of Persistent Classes|
The libraries of persistent classes are extensible libraries of elementary classes you use to define the database schema of your application. They include:
- Unicode (8-bit or 16-bit character type) strings
- Collections of any kind of persistent data such as arrays, stacks, queues, and graphs
All persistent classes are derived from the Persistent base class which defines a unique way of creating and handling persistent objects. You create new persistent classes by inheriting from this base class.
The translation functions allow you to convert persistent objects to transient ones and vice-versa.
These translation functions are used to build the Storage and Retrieval drivers of the application.
For each class of 2D and 3D geometric types, and for the general shape class in the topological data structure library, there are corresponding persistent class libraries which allow you to easily translate your data.