1. Chapter 3
The DATA DIVISION

2. Chapter Objectives To familiarize you with
Ways in which data is organized in COBOL
Rules for forming data-names
Defining input and output files in DATA DIVISION
Defining storage for work fields and constants
Forming Data-Names
The FILE SECTION of the DATA DIVISION
Types of Data
WORKING-STORAGE SECTION of the DATA DIVISION

3. Interactive and Batch Programs
Fully Interactive Programs
Use ACCEPT to get input from keyboard
Use DISPLAY to display output on screen
Full Batch Programs
Get input from files on disk
Direct output to files on disk
Hybrid Programs
Use combination of interactive and batch input and output methods

4. COBOL Data Organization
Field - group of characters forming a meaningful unit or basic fact
Characters in a name or digits in an amount
Records - group of related fields
All fields related to customer
File - group of related records
Customer file made up of customer records

5. User-Defined Data-Name Rules
1 to 30 characters
Letters, digits, hyphens (-) only
No embedded blanks
At least one alphabetic character
May not begin or end with hyphen
May not be COBOL reserved word

6. Identify the valid data-names
Date-Of-Birth
Amount$Out
Section
-First-Name
98-6
Time out

7. Data-Name Guidelines
Use meaningful data-names that describe contents of field
Amount-Due-In instead of A1
Use prefixes or suffixes in data-names when appropriate
-IN and -OUT for fields (Emp-Salary-IN and Emp- Salary-OUT)
-FILE and -RECORD for file and record names (Emp-File and Emp-Record)

8. DATA DIVISION Defines, describes storage for all data
Two main sections
FILE SECTION
Defines all input and output files, records, fields
Required for any program that uses files, typically batch programs
WORKING-STORAGE SECTION
Defines constants, end-of-file indicators and work areas
Defines fields not part of input or output files

9. Types of Files to Define
Input files
Master files
Transaction files -> updates
Output files
New Master files -> mix the two to get
Report files

10. File Description Entries
Each file described with an FD (File Descriptor) sentence
One FD for each SELECT statement in ENVIRONMENT DIVISION
FD followed by
File-name
Optional clauses to describe file and format of its records

11. File Description Format
FD file-name
RECORD IS OMITTED
LABEL
RECORDS ARE STANDARD
RECORD CONTAINS integer-1 CHARACTERS
BLOCK CONTAINS integer-2 RECORDS .

12. File Description clauses
LABEL RECORDS clause
Used if labels stored in file (OS will handle this for us, so we won’t use this clause)
BLOCKS CONTAINS clause
Indicates blocking factor for disk files (We won’t be using this clause) Has to do with disks that store data relative to blocks.
Just in case you see it later.

13. RECORD CONTAINS clause
Indicates size of each record
Optional but recommended since it provides check on record size
Given this FD
FD Sales-File
Record Contains 75 Characters.
If PICTURE clauses mistakenly add up to 76, compiler will report a syntax error

14. Defining a Record
Each FD (File Descriptor) followed by record description entries for the file
Data grouped in COBOL by levels
Record-name defined at the 01 level
Considered highest level of data
Fields within a record defined at subordinate level with level numbers from 02 to 49

15. Record Description Example
01 Employee-Rec-In Name-In … Annual-Salary-In … Job-Description-In …
Fields at 05 level subordinate to 01 level entry
All fields at same level (05), independent or not subordinate to each other
Leave room in numbering in case you need to add in between.

16. SELECT, FD, 01 entries & fields
REVIEW:
SELECT names file, assigns it to hardware device
FD describes file
01 names record
02-49 describes fields within record

17. Elementary and Group Items
Items defined with a level number are one of two types
Elementary item - field that is not further subdivided
Must include a PICTURE clause
Group item - field that is further subdivided
Has no PICTURE clause

18. Elementary and Group Items
01 Employee-Rec-In Name-In …
10 First-Name-In (Picture clause)
10 Last-Name-In (Picture clause) Annual-Salary-In (Picture clause)
Name-In is group item since it is subdivided into first and last name
Employee-Rec-In also group item
First-Name-In is elementary item since it is not further subdivided

19. Invalid Level Numbers 01 Employee-Rec-In. 05 Name-In …
10 First-Name-In (Picture clause)
12 Last-Name-In (Picture clause) Annual-Salary-In (Picture clause)
Last-Name-In level number is invalid since it is not subordinate to First-Name-In
Makes no sense because First-Name-In wouldn’t have a PIC clause and same indentation
Both first and last name are at same level and should have same level number

20. PICTURE (PIC) clauses Specify type of data stored in field
Indicate size of field

21. Types of data fields Alphabetic Alphanumeric Numeric
Only letters or blanks
For name, item description, etc.
Alphanumeric
Any character - letters, digits, special characters
For an address like 123 N. Main St.
Numeric
Only digits
For fields used in arithmetic operations

22. Data Types in PICTURE clause
A for alphabetic
X for alphanumeric
9 for numeric

23. Size of Data Fields Denote size of field by:
Number of A’s, X’s or 9’s used in PICTURE
01 Cust-Rec-In.
05 Cust-ID-In Picture XXXX.
05 Amt-In Picture

24. Size of Data Fields My also denote size of field by:
A, X or 9 followed by number in parentheses
01 Cust-Rec-In.
05 Cust-ID-In Picture X(4).
05 Amt-In Picture 9(5).

25. Defining Fields in Record
Must account for all positions defined in record layout
Must describe fields in order they appear in record
Field names should be unique
For fields not used by program
Data-name may be left blank (preferable)
May use reserved word FILLER as data-name
Positions must still be defined using PIC clause
Common for printing/display

26. Implied Decimal Point For fields used in arithmetic operations
Symbol V used in PIC clause to denote location of implied decimal point
Decimal point itself not stored as part of number
To store value in field AMT-IN, code entry as Amt-In Pic 99V99.

27. Variable and Constant Data
Entries in DATA DIVISION reserve storage for data
Entries in FILE SECTION reserve storage for data from records in input/output files
WORKING-STORAGE SECTION reserves storage for keyed input/output

28. Constant Data Data with a fixed value
Value that does not depend on input
Examples:
Fixed tax rate of .05
Message “INVALID” displayed when a value is in error
.05 and “INVALID” are constant values

29. Types of Constants Numeric literal Nonnumeric (alphanumeric) literal
Examples:
Constant used for arithmetic operations
Nonnumeric (alphanumeric) literal
Examples: “INVALID” “Enter your name”
Figurative constant
SPACES ZEROS
Reserved word for commonly used values

30. Rules for Nonnumeric Literals
Must be enclosed in quotation marks
From 1 to 160 characters, including space
Any character in COBOL character set except quotation mark Valid Nonnumeric Literals '123 Main St.' '$14.99' '12,342' 'Enter a value from 1 to 10'

31. Nonnumeric Literals
Only characters within quotes are moved or displayed
May contain all numbers ('125') but not same as numeric literal (125)
Cannot be used in arithmetic operations
Cannot be moved to field with PIC of 9’s
Are not data-names
'Amount-In' not same as field defined in DATA DIVISION called Amount-In

32. Figurative Constants - ZERO
ZERO, ZEROS or ZEROES means all zeros
Move Zeros To Total-Out
Fills each position in Total-Out with a zero
May be used with both numeric and alphanumeric fields
Example

33. Figurative Constants - SPACE
SPACE or SPACES means all spaces or blanks
Move Spaces To Code-Out
Fills each position in Code-Out with a space or blank
Use only with alphanumeric fields since blank is invalid numeric character
Example

34. WORKING-STORAGE SECTION
Follows FILE SECTION
Begins with heading on line by itself
Starts in Area A, ends with period
All items must be defined at 01 level or in entries subordinate to 01 level entry

35. WORKING-STORAGE SECTION
Rules for user-defined data-names apply
Elementary items:
Must include PICTURE clause
May be assigned initial value with VALUE clause

36. Uses of WORKING-STORAGE
To define fields used for
Keyed input and displayed output
Intermediate arithmetic results
Counters and totals
End-Of-File Indicators

37. VALUE clause To define initial value for field
If omitted, field’s value undefined when program begins execution
May be used only in WORKING-STORAGE SECTION

38. VALUE vs MOVE VALUE clause used in DATA DIVISION
Gives initial value before execution begins
MOVE used in PROCEDURE DIVISION
Assigns value to field after program begins
MOVE may change initial value of field

39. VALUE Clause Contains literal or figurative constant
Data type must match PICTURE
Numeric literals or ZEROS used with PIC 9 fields
01 WS-Tax-Rate Pic V99 Value .06.
01 WS-Total Pic 999 Value Zeros.
Nonnumeric literals, ZEROS or SPACES used with PIC X fields
01 WS-EOF Pic X(3) Value ‘YES’.
01 WS-Descrip Pic X(8) Value Spaces.

40. Defining Constants or Literals
Define a literal of .28 (28%) for a tax rate
Method 1 - code as literal in PROCEDURE DIVISION
Multiply .28 by WS-Salary Giving WS-Tax
Method 2 - store in data item in WORKING- STORAGE SECTION
01 WS-Rate Pic V99 Value .28.

41. Defining Constants or Literals
Method 2 - use data-name in place of literal in PROCEDURE DIVISION
Multiply WS-Rate by WS-Salary Giving
WS-Tax
Preferable for literals used more than once
Reduces likelihood of error since literal value entered one time
Allows meaningful name to be associated with number

42. Continuation of Literals
Nonnumeric literals may be up to 160 characters
Long literals may not fit on one typed line
Subdividing long literals into separate fields is recommended
You may need this when making a long sentence.

43. Continuation of Literals
Separate this report title into two fields
"Transaction Report for XYZ Corporation"
01 Report-Title.
Pic X(18) Value 'Transaction Report'.
Pic X(20) Value ' for XYZ Corporation'.
Example

44. Continuation of Literals
Long literals may be continued from one line to next, although this is not recommended
Rules for continuation of literals from one line to next
Begin literal with quotation mark.
Continue literal to position 72. Do not end with quotation mark.
Place hyphen on next line in position 7.
Continue literal with quotation mark starting anywhere in Area B.
End literal with quotation mark.
Example p. 92

45. COBOL 2008 Changes LABEL RECORDS clause will be phased out entirely
VALUE clause will be allowed in FILE SECTION
Way to continue nonnumeric literals will change
Margins A and B rules will be guidelines rather than requirements
Commas and dollar signs will be permissible in numeric literals

46. Chapter Summary Data organized into files, records and fields
Variable data changes with each run depending on input values
Constant or literal data defined within program, not entered as input

47. Chapter Summary
FILE SECTION includes FD entry for each file used by program
Record names coded at 01 level
Field names coded at level
Fields must be defined in order they appear in record

48. Chapter Summary Group items are further subdivided
Elementary items are not subdivided
Elementary items have PICTURE clause
Codes X, A, 9, V used to describe data

49. Chapter Summary WORKING-STORAGE SECTION used for storing
Intermediate results, counters
End-of-file indicators
Interactive data accepted as input or displayed
VALUE clauses may be used in this section to initialize fields