You use file-level, record-level, field-level, and key-field-level
entries to define a physical file with DDS.
A physical file can contain only one record
format. Follow these instructions to define a physical file:
- Specify the record format in either of the following two
ways:
- Define a new record format.
Specify field and key-field
specifications as required for the new record format.
- Share an existing record format.
Use the FORMAT keyword
to specify that the operating system is to use a previously defined record
format from another physical file. When the FORMAT keyword is used, you must
specify key-field level specifications again (if a keyed access path is required)
even if they were specified on the existing record format.
- Specify the entries in the following order to define a physical
file:
- File-level entries
- Record-level entries
- Field-level entries
- Key field-level entries
Note: The file name is specified through the Create Physical File
(CRTPF) command, not through DDS.
The maximum number
of fields in a record format is 8000. If any of the fields in the record format
are date, time, timestamp, variable length, or allows the null value, then
the actual maximum number of fields can be less than 8000. The maximum number
of fields can vary depending on the number of fields and combinations of fields
that occur within the record format. The maximum number of bytes in a record
format is 32 766 if variable length fields are not included and 32 740
if variable length fields are included.