Most standard Master File attributes are used with sequential data sources in the standard way. For more information, see Identifying a Data Source, Describing a Group of Fields, and Describing an Individual Field.
The SEGTYPE value for fixed-format data sources has a default of S0. However, if you use keyed retrieval, the SEGTYPE value depends on the number of keys and sort sequence. See Describing a FOCUS Data Source, for a description of the SEGTYPE attribute. For a description of keyed retrieval from fixed-format data sources, see the Creating Reports With WebFOCUS Language manual.
Note that file and segment declarations are optional for simple sequential data sources that you are not joining. However, they are recommended in order to make the data source description self-documenting, and to give you the option of joining the data source in the future.