DDS concepts

This topic provides an overview of data description specifications (DDS) on iSeries™ servers.

A traditional means of describing data attributes (such as the names and lengths of records and fields) is to specify the data attributes in the application programs themselves. However, a convenient and powerful alternative is available on iSeries servers. Data description specifications (DDS) describe data attributes in file descriptions that are external to the application program that processes the data.

The file types that use DDS are physical and logical files, display files, printer files, and intersystem communications function (ICF) files.

• Printable PDF
  Use this to view and print a PDF of this information.
• Create a file using data description specifications (DDS)
  Use these steps to create a file using DDS.
• DDS coding rules, conventions, and terms
  When you describe data attributes with DDS, you need to be aware of specific coding rules, naming conventions, and terminology.
• General considerations for using DBCS text with DDS files
  These topics describe the general considerations for positional entries, keyword entries, double-byte character set (DBCS) text literals, and DDS computer printouts that contain DBCS characters.
• Examples: DDS coding
  These topics include a wide variety of examples that illustrate how you can use DDS.
• When to specify REF and REFFLD keywords for DDS files
  This topic provides information to help you decide if you want to specify the REF (reference) or REFFLD (referenced field) keyword or both. It also tells you how to specify parameter values for each REF or REFFLD keyword you specify.
• Related information for DDS concepts
  Listed here are the product manuals (in PDF format) and information center topics that relate to the DDS concept topic. You can view or print any of the PDFs.