Organization of entries in the Data Division
Data description entry is the general term for the description of every single data item in the Data Division; the entry is composed of the level number, followed by a data-name (if necessary) and several data clauses.
The record description entry is used to define all data description entries which are associated with a particular record; that is, the record description entry describes all properties of that record. The type description entry is a special form of record description entry. It is used as a pattern which can be reused in other record description entries.
Level numbers are used in structuring a logical record so that subdivisions of the record may be referenced. Once a record has been subdivided, this structuring may be carried further to permit even more detailed data references.
Table 13 shows the permitted level numbers and their associated Data Division entries.
Level-number | Use |
01 | Record description entries |
02 - 49 | Data description entries describing subdivisions of a record |
77 | Description entries for independent or noncontiguous data items which are not subdivisions of other items and are not themselves subdivided |
66 | Elementary items or group items described by the RENAMES clause for the purpose of regrouping data items (see section "RENAMES clause") |
88 | Condition-name entries to specify condition-names associated with particular values of a conditional variable (see section "VALUE clause") |
Table 13: Meaning of level numbers
Consecutive data description entries may have the same format as the first such entry or may be intended according to their level numbers. While indentation is helpful for documentation purposes, it does not affect the compiler.
Multiply-defined 01- and 77-level record description entries are not treated as errors, provided they are not used in the Procedure Division. Multiply-defined type description entries are not treated as errors if they are not used in a TYPE clause or in the USAGE clause for type-specific data pointers.
The concept of level is contained in the structure of a logical record. This concept arises from the need of assigning names to the parts of a record in order to access them. Once a record has been thus subdivided, the subdivision can be carried further to permit even more detailed data references.
A "report group" is to the REPORT SECTION what a "record" is to other sections of the Data Division. The report group description entry describes all data description entries associated with a particular report group. Within a report group description entry, a distinction is made between the first and the subsequent data description entries (see chapter "Report Writer").
Those components of a record which are not further subdivided are called elementary items; a record thus either consists of a sequence of elementary items or is itself an elementary item.
An elementary item may be at the most 131071 characters long.
In order to reference a number of elementary items at one time, these items are arranged into "groups" or "group items". These groups may in turn be arranged into sets of two or more groups. Consequently, an elementary item may belong to more than one group.
The word "data item" is used in those cases where there is no need to distinguish between elementary and group items.
Data items that bear no hierarchical relationship to one another are defined as independent elementary items in conjunction with the level number 77.
In addition to the mandatory clauses, additional data clauses can be used to complete the data description entry. Their use is described in section "Clauses for data description".