Introduction to NATURAL.pdf

8/14/2019 Introduction to NATURAL.pdf

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Introduction to NATURAL

02/07/2009

This document gives a basic introduction to NATURAL programming.

Details what is NATURAL, NATURAL Data areas, NATURAL Variables and Statements.

Insurance / ISU 01

Lise Molineus Jaicy .P

[email protected]
mailto:[email protected]:[email protected]:[email protected]


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What is NATURAL?

NATURAL is a 4th generation programming language. It is free format language whereit can be either procedural or non-procedural. Can be used to build both online and batch

programs. Databases like ADABAS and DB2 can talk to NATURAL. There are two modes of

NATURAL programming, Structured and Reporting. The functional differences between

structured mode and reporting mode are provided at the end of the document.

Defining Data in NATURAL

Types of Variables and Data Areas

Defining Database Views

Defining User Variables

Redefinition Of Variables

Types of Variables:

Type Format Size

Alphanumeric (Annn) 1-253 characters

Numeric (Nnn.m) 1-29 digitsPacked decimal (Pnn.m) 1-29 digitsControl (C) 2-byte internal formatLogical (L) 1-byte FALSE/TRUE

Date (D) P6Time (T) P12

Floating Point (Fn) 4 bytes for single precision

Integer (In) 8 bytes for double precision or 1,2 or 4 bytesBinary (B) 1-128 bytes

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Example:

DEFINE DATA LOCAL

01 #NAME (A25)

01 #EMP-ID (N10)

END-DEFINE

DATA Areas:

The data areas are used to maintain external NATURAL Data Definitions. Following are the

three data areas.

LDA (Local Data Area)

Data resides within the program and is used in the program itself.

GDA (Global Data Area)

Data resides in a common location and is shared by all Natural objects

in the application

PDA (Parameter Data Area)

Data passed between a natural program and its subprogram, subroutine or a help

routine.

Local Data Area

Variables defined as local can be used only within a single NATURAL module.

There are two options for defining local data:

Defining the data within the program.

Defining the data in a local data area outside the program.

In the below example, the fields are defined within the DEFINE DATAstatement of the program. In the second example, the same fields are defined in a

local data area, and the DEFINE DATA statement only contains a reference to that data

area.

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Example 1 - Fields Defined within a DEFINE DATA Statement:

DEFINE DATA LOCAL

01 #EMP-ID (N20)

01 #EMP-NAME (A25)

01 #EMP-ADDR (A20)

01 #EMP-CITY (A25)

01 #EMP-SAL (P9.2)

END-DEFINE

Example 2 - Fields Defined in a local data area outside the program.

Sample LDA:

01 #INPUT-FILE A 28

R 01 #INPUT-FILE

02 #GRP-NUM N 9.0

02 #EMP-NO N 9.0

02 #EMP-NAME A 10

Program reference:

DEFINE DATA

LOCAL USING SAMPLDA

END-DEFINE

Global Data Area

The data elements that are to be used by more than one program, routine should be

defined in a global data area. Variables defined in a global data area may be

referenced by several objects in an application. The global data area and the objects

which reference it must be in the same library. Global data areas must be defined with

the data area editor, and a program using that data area must reference it in the

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DEFINE DATA statement. Any number of main programs, external subroutines and

help routines can share the same global data area.

Each object can reference only one global data area; that is, a DEFINE DATA statement

must not contain more than one GLOBAL clause.

Example:

DEFINE DATA

GLOBAL USING SAMPLGDA

END-DEFINE

Parameter Data Area

Parameter data areas are used by subprograms and external subroutines. Asubprogram is invoked with a CALLNAT statement. With the CALLNAT statement,

parameters can be passed from the invoking object to the subprogram. These

parameters must be defined with a DEFINE DATA PARAMETER statement in the

subprogram: they can be defined in the PARAMETER clause of the DEFINE DATA

statement itself; or they can be defined in a separate parameter data area, with the

DEFINE DATA PARAMETER statement referencing that parameter data area.

The sequence, format and length of the parameters specified with the CALLNAT/

PERFORM statement in the invoking object must exactly match the sequence, format

and length of the fields specified in the DEFINE DATA PARAMETER statement of theinvoked subprogram/subroutine. However, the names of the variables in the invoking

object and the invoked subprogram/subroutine need not be the same (as the

parameter data are transferred by address, not by name).

Sample PDA:

01 # GRP-DET A 28

R 01 # GRP-DET

02 #GRP-NUM N 9.0

02 #EMP-NO N 9.0

02 #EMP-NAME A 10

Program reference:

DEFINE DATA

PARAMETER USING SAMPLPDA

END-DEFINE

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Defining Database Views

View consists of database fields to be referenced.

It can be same as defined in DDM

May define own subset of DDM

May use same database fields in different view

May be defined internal or external (using data areas).

SYNTAX:

View-name VIEW [OF] DDM-name

{ level {ddm-field [(format length)] }

Example:

1 FX-BOOK VIEW OF GTI-FX-BOOK

2 TRAN-TYPE

2 GTD-RECEIPT-IND

2 REDEFINE GTD-RECEIPT-IND

3 #RECEIPT-IND (A1)

2 SOURCE-SYSTEM

2 C*CHANGE-HISTORY-GROUP

2 CHANGE-HISTORY-GROUP (1:99)

3 PREVIOUS-CHANGE-USER3 PREVIOUS-CHANGE-DATE

Defining User Variables

Variables can be defined and used when required and now that we know the data types the

variables can fit in, lets see how to use them.

For Example:

DEFINE DATA LOCAL

01 #NAME (A25)

01 #EMP-ID (N10)

01 #EMP-SAL (N10.2)

END-DEFINE

The variables should be declared within the DEFINE DATA and END-DEFINE section. The

variables can be used only when declared. NATURAL throws a syntax error if variables are used

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without declaring them initially. The layouts of input file / output file and other working

storage variables can be declared and used.

In the above example, the variable #NAME is alphanumeric and of size 25, which means that

it can hold names that have 25 characters or less.

Re-defining User Variables

Now that we know how to define variables, and if you observe closely they are not just

defined, but defined in levels. Weve seen examples where the variables are declared in 01

level. A variable can be redefined and can have sublevels.

Let us take the same example and try redefining the 01 level variable.

DEFINE DATA LOCAL

01 #NAME (A25)

01 REDEFINE #NAME

02 # FORE-NAME (A10)

02 # SURNAME (A15)

01 #EMP-ID (N10)

01 #EMP-SAL (N10.2)

END-DEFINE

The name comprises of two parts, forename and surname. The above redefinition shows that

the forename is alphanumeric and of size 10 and surname is alphanumeric and of size 15 and

both adds up to 25 characters.

NATURAL Statements

Lets have a look at some of the most frequently used NATURAL Statements in detail.

ACCEPT/REJECT

Syntax:

ACCEPT IF logical-condition

REJECT IF logical-condition

Example:

READ EMPLOY-VIEW

ACCEPT IF#SEX = 'F' AND #MAR-STAT = 'S'

DISPLAY #NAME

END-READ

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ADD

Syntax:

ADD ROUNDED operand1 ... TO operand2

ADD ROUNDED operand1 ... GIVING operand2

Example:

ADD+5 -2 -1 GIVING #A #A: 2

ADD.231 3.6 GIVING #B #B: 3.8

ADDROUNDED 2.9 3.8 GIVING #C #C: 7

SUBTRACT

Syntax:

SUBTRACT ROUNDED operand1 ... FROM operand2

SUBTRACT ROUNDED operand1 ... FROM operand2 GIVING operand3

Example:

DEFINE DATA LOCAL

1 #A (P2) INIT

1 #B (P2)

1 #C (P1.1) INIT

END-DEFINESUBTRACT 6 FROM #A #A: 44

SUBTRACT6 FROM 11 GIVING #A #A: 5

SUBTRACT 3 4 FROM #A GIVING #B #A: 5 #B: -2

SUBTRACT -3 -4 FROM #A GIVING #B #A: 5 #B: 12

SUBTRACTROUNDED 2.06 FROM #C #C: 0.3

MULTIPLY

Syntax:MULTIPLY ROUNDED operand1 BY operand2

MULTIPLY ROUNDED operand1 BY operand2 GIVING operand3

Example:

MULTIPLY#A BY 3 GIVING #C

MULTIPLYROUNDED 3 BY 3.5 GIVING #C

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DIVIDE

Syntax:

DIVIDE ROUNDED operand1 INTO operand2 GIVING operand3

DIVIDE operand1 INTO operand2 GIVING operand3 REMAINDER operand4

Example:

DEFINE DATA LOCAL

1 #A (N7) INIT

1 #B (N7)

1 #C (N3.2)

1 #D (N1)

1 #E (N1) INIT

1 #F (N1)END-DEFINE

DIVIDE5 INTO #A GIVING #B #B: 4

DIVIDE 3 INTO 3.1 GIVING #D #D: 1

DIVIDE2 INTO #E REMAINDER #F #E: 1 #F: 1

READ

Syntax:

READ operand1 RECORDS IN FILE view-name

sequence/range-specification

STARTING WITH ISN=operand4

WHERE-clause

statement ...

END-READ

Example:

READEMPLOY-VIEW BY ISN STARTING FROM 1 ENDING AT 3

DISPLAY PERSONNEL-ID NAME *ISN *COUNTER

END-READ

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READEMPLOY-VIEW IN PHYSICAL SEQUENCE

DISPLAY PERSONNEL-ID NAME *ISN *COUNTER

END-READ

FIND

Syntax:

FIND |option| RECORDS IN FILE view-name

WITH-clause

STARTING WITH ISN=operand5

END-FIND

Example:

FINDEMPLOY-VIEW WITH CITY = `FRANKFURT`DISPLAY FIRST-NAME PERSONNEL-ID

END-FIND

STORE

Syntax:

STORE RECORD IN FILE view-name

WITH FIELD-NAME = Value

END-TRANSACTION

Example:

STORERECORD IN EMPLOYEES

WITH PERSONNEL-ID = #PERSONNEL-ID

NAME = #NAME

FIRST-NAME = #FIRST-NAME

MAR-STAT = #MAR-STAT

BIRTH = #BIRTH

CITY = #CITY

END TRANSACTION

WRITE NOTITLE `RECORD HAS BEEN ADDED`

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UPDATE

Syntax:

UPDATE RECORD IN STATEMENT (r)

Example:

FIND EMPLOY-VIEW WITH NAME = #NAME

MOVE CHENNAI to #CITY

UPDATE

END TRANSACTION

END-FIND

DELETE

Syntax:

DELETE RECORD IN STATEMENT (r) )

Example:

FIND EMPLOY-VIEW WITH NAME = #NAME

IF EMP-ID EQ 52103

DELETE

END TRANSACTION

END-IF

END-FIND

END TRANSACTION

Syntax:

END OF TRANSACTION operand1 ...

Example:

FIND EMPLOY-VIEW WITH CITY = `BOSTON`

ASSIGN COUNTRY = `USA`UPDATE

END TRANSACTION

END-FIND

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READ WORK FILE x

Syntax:

READ WORK FILE work-file-number ONCE RECORD operand1

statement...

statement...

statement...

END-WORK

Example:

READ WORK FILE1 RECORD #RECORD

DISPLAY NOTITLE #PERS-ID #NAME

END-WORK

CLOSE WORK FILE

Syntax:

CLOSE WORK FILE work-file-number

Example:

READ WORK FILE 1 ONCE #W-DAT

AT END OF FILE

WRITE '*** END OF FILE ***'

END-ENDFILE

WRITE #W-DAT

INPUT 'FROM START (Y/N) ?' #PRMPT

IF #PRMPT NE 'Y' THEN STOP END-IF

CLOSE WORK FILE 1

WRITE WORK FILESyntax:

WRITE WORK FILE work-file-number VARIABLE operand1 ...

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Example:

FIND EMPLOY-VIEW WITH CITY = `LONDON`

WRITE WORK FILE 1PERSONNEL-ID NAME

END-FIND

CALLNAT

Syntax:

CALLNAT operand1 USING operand2

Example:

/* MAIN PROGRAM `MAINP1`

DEFINE DATA LOCAL

1 #FIELD1 (N6)

1 #FIELD2 (A20)

1 #FIELD3 (A10)

CALLNAT `SUBP1` #FIELD1 (AD=M) #FIELD2 (AD=O) #FIELD3 `P4 TEXT`

/* SUBPROGRAM `SUBP1`

DEFINE DATA PARAMETER

1 #FIELDA (N6)

1 #FIELDB (A20)

1 #FIELDC (A10)

END-DEFINE

DECIDE ON

Syntax:

DECIDE ON FIRST VALUES OF operand1

EVERY

VALUES operand2 ,operand2... :operand2 statement... ...ANY VALUES statement...

ALL VALUES statement...

NONE VALUES statement...

IGNORE

END-DECIDE

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Example:

DECIDE ON FIRST VALUE OF *PF-KEY

VALUE `PF1`

PERFORM ROUTINE-UPD

VALUE `PF2`

PERFORM ROUTINE-ADD

ANY VALUE

END TRANSACTION

WRITE `RECORD HAS BEEN MODIFIED`

NONE VALUE

IGNORE

END-DECIDE END

Syntax:

END

Example:

FIND ...

READ ...

END-READ

END-FIND

END

ESCAPE

Syntax:

ESCAPE TOP

BOTTOM (r) IMMEDIATE

ROUTINE IMMEDIATE

Example:

FND. FIND EMPLOY-VIEW WITH CITY = #CITY

IF NO RECORDS FOUND

WRITE `NO RECORDS FOUND`

ESCAPE BOTTOM (FND.)

END-NOREC

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IF #CNTL = 'D'

ESCAPE BOTTOM (FND.)

END-IF

END-FIND

FOR

Syntax:

FOR operand1 = operand2 TO operand3 STEP operand4

statement ...

END-FOR

Example:

DEFINE DATA LOCAL

1 #INDEX (I1) INIT 1 #ROOT (N2.7)

END-DEFINE

FOR#INDEX 1 TO 5

COMPUTE #ROOT = SQRT (#INDEX)

WRITE NOTITLE `=` #INDEX 3X `=` #ROOT

END-FOR

IF

Syntax:

IF logical-condition

THEN statement ...

ELSE statement ...

END-IF

Example:

IFSALARY (1) LT 40000

WRITE NOTITLE `*****` NAME 30X `SALARY LT 40000`

ELSE

IFBIRTH GT 300101

FIND VEHIC-VIEW WITH PERSONNEL-ID = PERSONNEL-ID (FND.)

DISPLAY NAME BIRTH SALARY

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END-FIND

END-IF

END-IF

MOVE

Syntax:

1. MOVE ROUNDED operand1 (parameter) TO operand2

2. MOVE BY NAME operand1 TO operand2

3. MOVE BY POSITION operand1 TO operand2

4. MOVE EDITED operand1 TO operand2 (EM=value)

5. MOVE EDITED operand1 (EM=value) TO operand2

Examples:

MOVE 'ABCDE' TO #A(A5) #B(A2) #A: ABCDE #B: ABMOVE ROUNDED 1.995 TO #E(N1) #E: 2

MOVE'ABCDE'(PM=I) TO SUBSTRING (#F,1,4) #F: EDCB

MOVEEDITED '003.45' TO #G (EM=999.99) #G: 3.45

MOVERIGHT JUSTIFIED 'ABCDE' TO #H(A3) #H: CDE

RESET

Syntax:

RESET INITIAL operand1 ...

Examples:

DEFINE DATA LOCAL

1 #BINARY (B4) INIT

1 #INTEGER (I4) INIT

1 #NUMERIC (N2) INIT

END-DEFINE

RESETNAME #BINARY #INTEGER #NUMERIC

RESETINITIAL #BINARY #INTEGER #NUMERIC

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Sample NATURAL Program:-

DEFINE DATA LOCAL

01 #NAME (A25)

01 REDEFINE #NAME

02 # FORE-NAME (A10)

02 # SURNAME (A15)

01 #INPUT-RECORD (N10)

01 REDEFINE #INPUT-RECORD

02 # INP-EMP-ID (N10)

01 #OUTPUT-RECORD (A80)

01 REDEFINE #OUTPUT-RECORD

02 #EMP-ID (N10)

02 #NAME (A25)

01 #EMP-SAL (N10.2)

END-DEFINE

READ WORK FILE 1 #INPUT-RECORD

MOVE LISA TO # FORE-NAME

MOVE SAMUELS TO # SURNAME

MOVE # INP-EMP-ID TO #EMP-ID

MOVE 3000000 TO #EMP-SAL

WRITE WORK FILE 2 #OUTPUT-RECORD

END-WORK

END.

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Functional Differences between Structured and Reporting Modes:

The major functional differences between structured mode and reporting mode are

summarized below:

Sl.no Structured Mode Reporting Mode

1. The syntax related to closing loops and

functional blocks differs in the two

modes. In structured mode, every loop

or logical construct must be explicitly

closed with a corresponding END-

...statement. Thus, it becomes

immediately clear, which loop/logical

constructs ends where.

Reporting mode uses (CLOSE) LOOP and DO ...

DOEND statements for this purpose.

END-... statements (except END-DEFINE, END-

DECIDE and END-SUBROUTINE) cannot be used in

Reporting mode, while LOOP and DO/DOEND

statements cannot be used in structured mode.

2. All data elements to be used have to bedefined in one central location (either

in the DEFINE DATA statement at the

beginning of the program or in a data

area outside the program).

One can use database fields without having todefine them in a DEFINE DATA statement; also,

you can define user-defined variables anywhere in

a program, which means that they can be

scattered all over the program.

The Natural Statements documentation provides separate syntax diagrams for each mode-

sensitive statement.

The two examples below illustrate the differences between the two modes in constructing

processing loops and logical conditions.

Reporting Mode Example:

The reporting mode example uses the statements DO and DOEND to mark the beginning and

end of the statement block that is based on the AT END OF DATA condition. The END

statement closes all active processing loops.

READ EMPLOYEES BY PERSONNEL-ID

DISPLAY NAME BIRTH POSITION

AT END OF DATA

DO

SKIP 2

WRITE / LAST SELECTED: OLD (NAME)

DOEND

END

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Structured Mode Example:

The structured mode example uses an END-ENDDATA statement to close the AT END OF DATA

condition, and an END-READ statement to close the READ loop. The result is a more clearly

structured program in which you can see immediately where each construct begins and ends:

DEFINE DATA LOCAL

1 EMPL VIEW OF EMPLOYEES

2 PERSONNEL-ID

2 NAME

2 BIRTH

2 POSITION

END-DEFINE

READ EMPL BY PERSONNEL-ID

DISPLAY NAME BIRTH POSITION

AT END OF DATA

SKIP 2

WRITE / LAST SELECTED: OLD (NAME)

END-ENDDATA

END-READ

END

Books Referred:

NATURAL Developers Handbook version 4.1.3.

I t l U 19

Documents

Introduction to NATURAL.pdf