Data division
Introduction#
DATA DIVISION is one of the four parts that make up a COBOL program. It contains statements describing the data used by the program. It consists of four sections: FILE SECTION, WORKING-STORAGE SECTION, LOCAL-STORAGE SECTION and LINKAGE SECTION.
Sections in Data Division
SECTIONs in COBOL can be required or optional, depending on which DIVISION they are in.
DATA DIVISION.
FILE SECTION.
FD SAMPLE-FILE
01 FILE-NAME PIC X(20).
WORKING-STORAGE SECTION.
01 WS-STUDENT PIC A(10).
01 WS-ID PIC 9(5).
LOCAL-STORAGE SECTION.
01 LS-CLASS PIC 9(3).
LINKAGE SECTION.
01 LS-ID PIC 9(5).In the above example, 01’s are level numbers.
Level Number
Level number is used to specify the level of data in a record. They are used to differentiate between elementary items and group items. Elementary items can be grouped together to create group items.
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01: Record description entry. Group level number is always 01.
DATA DIVISION. WORKING-STORAGE SECTION. 01 WS-NAME PIC X(25). ---> ELEMENTARY ITEM 01 WS-SURNAME PIC X(25). ---> ELEMENTARY ITEM
01 WS-ADDRESS. ---> GROUP ITEM
05 WS-HOUSE-NUMBER PIC 9(3). ---> ELEMENTARY ITEM 05 WS-STREET PIC X(15). ---> ELEMENTARY ITEM -
02 to 49: Elementary items
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66: Rename Clause items
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77: Items which cannot be sub-divided.
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88: Level 88 is a special level number used to improve the readability of COBOL programs and to improve IF tests. A level 88 looks like a level under another variable, but it’s not. It does not have a PICTURE, but it does have a value. A level 88 is always associated with another variable and is a condition name for that variable.
01 YES-NO PIC X. 88 ANSWER-IS-YES VALUE “Y”.
Both of the following conditions test whether YES-NO is equal to “Y”:
IF YES-NO = "Y"
IF ANSWER-IS-YESA level 88 condition name can be used for an alphanumeric or numeric variable.
Picture Clause
The PICTURE CLAUSE defines two things about a variable: the size of the variable (the number of bytes used in memory for the value) and the type of data that can be stored in the variable.