Data Structures are used to describe all data sets processed by
applications.
Data Structures are logical groups of Segments, which may be:
- Records of files,
- Work areas of Programs,
- Segments of databases,
- Inter-program common areas,
- Table items.
A Data Structure is described logically, with no physical characteristics.
This description may then be reused for different purposes:
Example: a given Segment may be used in a database and in the Programs
accessing to the database.
Information of physical nature (such as organization, block size, description
type, etc.) is added when the Data Structure is used in Programs or Database
Blocks.