Item; Record; Level Number - Control Data Corporation 3300 Reference Manual

3.2.2
ITEM
3.2.3
RECORD
3.2.4
LEVEL NUMBER
60229400
An item is an area used to contain data of a particular kind. The COBOL
language recognizes four kinds of items:
elementary
~..J ~..t ~ ~
group
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independent
report
Elementary items are items that are not subdivided into smaller items. A
group item is subdivided into smaller items which can themselves be group
or elementary items. Group and elementary items may be used in all sections
of the Data Division. Independent items are unrelated elementary items not
contained in a record; each is defined by the special level number 77. Inde-
pendent items are illegal in the File Section. Report items are group or
elementary items that appear in a report. They may be used only
in
the
Report Section (see Report Writer, section 5).
A record is the most inclusive item in the File, Working Storage or Common
Storage Sections.
It
is usually, but not necessarily a group item. A record
must have the level number 1 or 01 and a data name. Each item in a record
must have at least a level number and a data name. In addition, any elementary
items in a record must have at least a PICTURE or USAGE defined as INDEX,
COMPUTATIONAL-I, or COMPUTATIONAL-2. Data names of items not at
the 01 level in a record need not be unique if they can be made unique by
qualification. In the File Section only, data names at the 01 level need not be
unique since they can be qualified by a file name.
The level number shows the hierarchy of data within a record description;
the more inclusive an item, the lower its level number. Level numbers need
not be consecutive as long as the less inclusive item has the higher number.
The specific number is determined by the user. The first entry in a record
description always has the level number 1 or 01. Group and elementary items
within a record have level numbers in the range 2 -49.
Special level numbers are assigned to certain entries where there is no real
concept of level:
66 identifies RENAMES entries.
77 identifies independent items.
88 identifies condition -name entries.
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