Data Description Specifications (DDS) is a fixed-format language used by application programmers to code the source definitions for physical and logical database files, as well as display and printer files. This column-based language describes data attributes, such as names and lengths of fields, in file descriptions external to the application program that processes the data.
DDS allows you to create and access data descriptions and screen and report designs on an AS/400 server by defining files. Each file contains DDS specification statements which organize the data into records, and, in many cases, specific fields in the records. Whenever a DDS file is processed, the AS/400 business computing system will use this description.
This coding language uses records, fields, and keywords to display the details of a DDS file definition. Each specification statement depends on the type of file you are defining. Since the DDS language is position-dependant, the function and syntax of a DDS entry is relative to the column in which it is entered. For example, to signal a Comment specification in a display file, enter an asterisk (*) in position 7 of a DDS statement.
The DDS programming language has the advantage of providing the programmer with:
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