Physical realization is the process of mapping a logical application schema onto one or more devices to provide persistent storage. The physical layer of the DBMS architecture is concerned with actually storing the information exposed by the application, and providing efficient, transactional access to that information.
The Dataphor Server utilizes existing DBMSs as its physical, or internal, layer. In other words, the Dataphor Server uses SQL-based DBMSs as its file system. The internal layer of the Dataphor Product is based on an architecture called the Storage Integration Architecture (SIA).
This part is devoted to explaining how the SIA works, and how it enables the homogeneous data access achieved by the Dataphor Server. It also discusses concepts and techniques for mapping logical application schema into physical devices.
Although the SIA is capable of describing any storage system, the majority of the discussions in this part will focus on SQL-based devices in particular, as these form the bulk of the devices shipped with the Dataphor Product, and are generally more complex in nature than text or file-based devices.