A sample data description specifications form is printed in reduced size in Figure 1.
The left side of the DDS form (positions 1 through 44) is for fixed-format entries called positional entries. Positional entries define the most common attributes of record formats and fields, such as names and lengths of fields. For a brief description of the most important positional entries, see items (1) through (7) following the figure.
The right side of the DDS form (positions 45 through 80) is for DDS keywords. DDS keywords define less-common and more-varied attributes of files, record formats, and fields; they follow a subset of the syntax rules for control language. For a brief description of keyword entries, see item (8) following the figure.
Figure 1. Overview of the Positional Entries and Keywords
Name Entry | Description | Type of File |
---|---|---|
R | Specifies a record format name | All |
blank | Specifies a field name | All |
K | Specifies a key field name | Physical and logical only |
S | Specifies a select field name | Logical only |
O | Specifies an omit field name | Logical only |
J | Specifies this as a join specification | Join logical only |
H | Specifies this as a help specification | Display only |
Keywords Apply at This Level | For These Files |
---|---|
File | All types of files |
Record | All types of files |
Field | All types of files |
Join | Join logical files only |
Key field | Physical and logical files |
Select or omit field | Logical files only |
Help | Display files only |
For display and printer files, constants specified within apostrophes become the default values for displayed or printed fields.
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