The level-number shows the hierarchy of data within a logical record.
In addition, it is used to identify entries for working-storage items, linkage items, condition-names
, constant-names
and the RENAMES clause.
General Format
Syntax Rules
- A level-number is required as the first element in each data description entry.
- Data description entries subordinate to an FD or SD entry must have level-numbers with the values 01 through 49, 66
,78
or 88. (See the topic
File Description Entry Skeleton.)
- Data description entries in the Report Section and Screen Section must have level-numbers with the values 01 through 49
, or 78
- Data description entries in the Working-Storage Section
, Local-Storage Section
and Linkage Section must have level-numbers with the values 01 through 49, 66, 77
, 78
or 88.
- A level-number can be a one- or two-digit number.
General Rules
- The level-number 01 identifies the first entry in each record description.
- Special level numbers have been assigned to certain entries where there is no real concept of level hierarchy:
- The level-number 77 is assigned to identify noncontiguous working-storage data items and noncontiguous linkage data items. It can be used only as described by Format 1 of the data description skeleton earlier in this chapter.
- Level number 66 is assigned to identify RENAMES entries and can be used only as described in Format 2 of the data description skeleton earlier in this chapter.
- Level number 88 is assigned to entries which define condition-names associated with a conditional variable and can be used only as described in Format 3 of the data description skeleton earlier in this chapter.
- Level number 78 is assigned to entries which define constant-names. It can be used only as described in Format 4 of the data description skeleton earlier in this chapter.
- Multiple level 01 entries subordinate to an FD or SD entry represent implicit redefinitions of the same area.
