Introduction to COBOL
COBOL is a high-level language. One must understand the way COBOL works. Computers only understand machine code, a binary stream of 0s and 1s. COBOL code must be converted into machine code using a compiler. Run the program source through a compiler. The compiler first checks for any syntax errors and then converts it into machine language. The compiler creates an output file which is known as load module. This output file contains executable code in the form of 0s and 1s.
Evolution of COBOL
During 1950s, when the businesses were growing in the western part of the world, there was a need to automate various processes for ease of operation and this gave birth to a high-level programming language meant for business data processing.
- In 1959, COBOL was developed by CODASYL (Conference on Data Systems Language).
- The next version, COBOL-61, was released in 1961 with some revisions.
- In 1968, COBOL was approved by ANSI as a standard language for commercial use (COBOL-68).
- It was again revised in 1974 and 1985 to develop subsequent versions named COBOL-74 and COBOL-85 respectively.
- In 2002, Object-Oriented COBOL was released, which could use encapsulated objects as a normal part of COBOL programming.
Importance of COBOL
- COBOL was the first widely used high-level programming language. It is an English-like language which is user friendly. All the instructions can be coded in simple English words.
- COBOL is also used as a self-documenting language.
- COBOL can handle huge data processing.
- COBOL is compatible with its previous versions.
- COBOL has effective error messages and so, resolution of bugs is easier.
Features of COBOL
Standard Language
COBOL is a standard language that can be compiled and executed on machines such as IBM AS/400, personal computers, etc.
Business Oriented
COBOL was designed for business-oriented applications related to financial domain, defense domain, etc. It can handle huge volumes of data because of its advanced file handling capabilities.
Robust Language
COBOL is a robust language as its numerous debugging and testing tools are available for almost all computer platforms.
Structured Language
Logical control structures are available in COBOL which makes it easier to read and modify. COBOL has different divisions, so it is easy to debug.
COBOL – Environment Setup
We have set up the COBOL Programming environment online, so that you can compile and execute all the available examples online. It gives you confidence in what you are reading and enables you to verify the programs with different options. Feel free to modify any example and execute it online.ELEMENTARY ITEM 01 WS-CLASS PIC 9(2) VALUE ’10’. —> ELEMENTARY ITEM 01 WS-ADDRESS. —> GROUP ITEM 05 WS-HOUSE-NUMBER PIC 9(3). —> ELEMENTARY ITEM 05 WS-STREET PIC X(15). —> ELEMENTARY ITEM 05 WS-CITY PIC X(15). —> ELEMENTARY ITEM 05 WS-COUNTRY PIC X(15) VALUE ‘INDIA’. —> ELEMENTARY ITEM
Picture Clause
Picture clause is used to define the following items −
- Data type can be numeric, alphabetic, or alphanumeric. Numeric type consists of only digits 0 to 9. Alphabetic type consists of letters A to Z and spaces. Alphanumeric type consists of digits, letters, and special characters.
- Sign can be used with numeric data. It can be either + or .
- Decimal point position can be used with numeric data. Assumed position is the position of decimal point and not included in the data.
- Length defines the number of bytes used by the data item.
Symbols used in a Picture clause −
| Sr.No. | Symbol & Description |
|---|---|
| 1 | 9Numeric |
| 2 | AAlphabetic |
| 3 | XAlphanumeric |
| 4 | VImplicit Decimal |
| 5 | SSign |
| 6 | PAssumed Decimal |
Example
The following example shows the use of PIC clause −
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-NUM1 PICS9(3)V9(2).01 WS-NUM2 PICPPP999.01 WS-NUM3 PICS9(3)V9(2)VALUE-123.45.01 WS-NAME PICA(6)VALUE'ABCDEF'.01 WS-ID PICX(5)VALUE'A121$'.PROCEDUREDIVISION.DISPLAY"WS-NUM1 : "WS-NUM1.DISPLAY"WS-NUM2 : "WS-NUM2.DISPLAY"WS-NUM3 : "WS-NUM3.DISPLAY"WS-NAME : "WS-NAME.DISPLAY"WS-ID : "WS-ID.STOPRUN.
JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLO
When you compile and execute the above program, it produces the following result −
WS-NUM1 : +000.00 WS-NUM2 : .000000 WS-NUM3 : -123.45 WS-NAME : ABCDEF WS-ID : A121$
Value Clause
Value clause is an optional clause which is used to initialize the data items. The values can be numeric literal, alphanumeric literal, or figurative constant. It can be used with both group and elementary items.
Example
The following example shows the use of VALUE clause −
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-NUM1 PIC99V9VALUEIS3.5.01 WS-NAME PICA(6)VALUE'ABCD'.01 WS-ID PIC99VALUEZERO.PROCEDUREDIVISION.DISPLAY"WS-NUM1 : "WS-NUM1.DISPLAY"WS-NAME : "WS-NAME.DISPLAY"WS-ID : "WS-ID.STOPRUN.
JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLO
When you compile and execute the above program, it produces the following result −
WS-NUM1 : 03.5 WS-NAME : ABCD WS-ID : 00
COBOL – Basic Verbs
COBOL verbs are used in the procedure division for data processing. A statement always start with a COBOL verb. There are several COBOL verbs with different types of actions.
Input / Output Verbs
Input/Output verbs are used to get data from the user and display the output of COBOL programs. The following two verbs are used for this process −
Accept Verb
Accept verb is used to get data such as date, time, and day from the operating system or directly from the user. If a program is accepting data from the user, then it needs to be passed through JCL. While getting data from the operating system, FROM option is included as shown in the following example −
ACCEPT WS-STUDENT-NAME. ACCEPT WS-DATE FROM SYSTEM-DATE.
Display Verb
Display verb is used to display the output of a COBOL program.
DISPLAY WS-STUDENT-NAME. DISPLAY "System date is : " WS-DATE.
COBOL PROGRAM
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-STUDENT-NAME PICX(25).01 WS-DATE PICX(10).PROCEDUREDIVISION.ACCEPT WS-STUDENT-NAME.ACCEPT WS-DATE FROMDATE.DISPLAY"Name : " WS-STUDENT-NAME.DISPLAY"Date : " WS-DATE.STOPRUN.
JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLO //INPUT DD DSN=PROGRAM.DIRECTORY,DISP=SHR //SYSIN DD * TutorialsPoint /*
When you compile and execute the above program, it produces the following result −
Name : TutorialsPoint Date : 2014-08-30
Initialize Verb
Initialize verb is used to initialize a group item or an elementary item. Data names with RENAME clause cannot be initialized. Numeric data items are replaced by ZEROES. Alphanumeric or alphabetic data items are replaced by SPACES. If we include REPLACING term, then data items can be initialized to the given replacing value as shown in the following example −
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-NAME PICA(30)VALUE'ABCDEF'.01 WS-ID PIC9(5).01 WS-ADDRESS.05 WS-HOUSE-NUMBER PIC9(3).05 WS-COUNTRY PICX(15).05 WS-PINCODE PIC9(6)VALUE123456.PROCEDUREDIVISION. A000-FIRST-PARA.INITIALIZE WS-NAME, WS-ADDRESS.INITIALIZE WS-ID REPLACINGNUMERICDATABY12345.DISPLAY"My name is : "WS-NAME.DISPLAY"My ID is : "WS-ID.DISPLAY"Address : "WS-ADDRESS.DISPLAY"House Number : "WS-HOUSE-NUMBER.DISPLAY"Country : "WS-COUNTRY.DISPLAY"Pincode : "WS-PINCODE.STOPRUN.
JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLO
When you compile and execute the above program, it produces the following result −
My name is : My ID is : 12345 Address : 000 000000 House Number : 000 Country : Pincode : 000000
Move Verb
Move verb is used to copy data from source data to destination data. It can be used on both elementary and group data items. For group data items, MOVE CORRESPONDING/CORR is used. In try it option, MOVE CORR is not working; but on a mainframe server, it will work.
For moving data from a string, MOVE(x:l) is used where x is the starting position and l is the length. Data will be truncated if the destination data item PIC clause is less than the source data item PIC clause. If the destination data item PIC clause is more than the source data item PIC clause, then ZEROS or SPACES will be added in the extra bytes. The following example makes it clear.
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-NUM1 PIC9(9).01 WS-NUM2 PIC9(9).01 WS-NUM3 PIC9(5).01 WS-NUM4 PIC9(6).01 WS-ADDRESS.05 WS-HOUSE-NUMBER PIC9(3).05 WS-COUNTRY PICX(5).05 WS-PINCODE PIC9(6).01 WS-ADDRESS1.05 WS-HOUSE-NUMBER1 PIC9(3).05 WS-COUNTRY1 PICX(5).05 WS-PINCODE1 PIC9(6).PROCEDUREDIVISION. A000-FIRST-PARA.MOVE123456789TO WS-NUM1.MOVE WS-NUM1 TO WS-NUM2 WS-NUM3.MOVE WS-NUM1(3:6)TO WS-NUM4.MOVE123TO WS-HOUSE-NUMBER.MOVE'INDIA'TO WS-COUNTRY.MOVE112233TO WS-PINCODE.MOVE WS-ADDRESS TO WS-ADDRESS1.DISPLAY"WS-NUM1 : " WS-NUM1 DISPLAY"WS-NUM2 : " WS-NUM2 DISPLAY"WS-NUM3 : " WS-NUM3 DISPLAY"WS-NUM4 : " WS-NUM4 DISPLAY"WS-ADDRESS : " WS-ADDRESS DISPLAY"WS-ADDRESS1 : " WS-ADDRESS1 STOPRUN.
JCL to execute the above COBOL program.
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLO
When you compile and execute the above program, it produces the following result −
WS-NUM1 : 123456789 WS-NUM2 : 123456789 WS-NUM3 : 56789 WS-NUM4 : 345678 WS-ADDRESS : 123INDIA112233 WS-ADDRESS1 : 123INDIA112233
Legal Moves
The following table gives information about the legal moves −
| Alphabetic | Alphanumeric | Numeric | |
|---|---|---|---|
| Alphabetic | Possible | Possible | Not Possible |
| Alphanumeric | Possible | Possible | Possible |
| Numeric | Not Possible | Possible | Possible |
Add Verb
Add verb is used to add two or more numbers and store the result in the destination operand.
Syntax
Given below is the syntax to Add two or more numbers −
ADD A B TO C D ADD A B C TO D GIVING E ADD CORR WS-GROUP1 TO WS-GROUP2
In syntax-1, A, B, C are added and the result is stored in C (C=A+B+C). A, B, D are added and the result is stored in D (D = A + B + D).
In syntax-2, A, B, C, D are added and the result is stored in E (E=A+B+C+D).
In syntax-3, sub-group items within WS-GROUP1 and WS-GROUP2 are added and the result is stored in WS-GROUP2.
Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-NUM1 PIC9(9)VALUE10.01 WS-NUM2 PIC9(9)VALUE10.01 WS-NUM3 PIC9(9)VALUE10.01 WS-NUM4 PIC9(9)VALUE10.01 WS-NUMA PIC9(9)VALUE10.01 WS-NUMB PIC9(9)VALUE10.01 WS-NUMC PIC9(9)VALUE10.01 WS-NUMD PIC9(9)VALUE10.01 WS-NUME PIC9(9)VALUE10.PROCEDUREDIVISION.ADD WS-NUM1 WS-NUM2 TO WS-NUM3 WS-NUM4.ADD WS-NUMA WS-NUMB WS-NUMC TO WS-NUMD GIVING WS-NUME.DISPLAY"WS-NUM1 : " WS-NUM1 DISPLAY"WS-NUM2 : " WS-NUM2 DISPLAY"WS-NUM3 : " WS-NUM3 DISPLAY"WS-NUM4 : " WS-NUM4 DISPLAY"WS-NUMA : " WS-NUMA DISPLAY"WS-NUMB : " WS-NUMB DISPLAY"WS-NUMC : " WS-NUMC DISPLAY"WS-NUMD : " WS-NUMD DISPLAY"WS-NUME : " WS-NUME STOPRUN.
JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLO
When you compile and execute the above program, it produces the following result −
WS-NUM1 : 000000010 WS-NUM2 : 000000010 WS-NUM3 : 000000030 WS-NUM4 : 000000030 WS-NUMA : 000000010 WS-NUMB : 000000010 WS-NUMC : 000000010 WS-NUMD : 000000010 WS-NUME : 000000040
Subtract Verb
Subtract verb is used for subtraction operations.
Syntax
Given below is the syntax for Subtract operations −
SUBTRACT A B FROM C D SUBTRACT A B C FROM D GIVING E SUBTRACT CORR WS-GROUP1 TO WS-GROUP2
In syntax-1, A and B are added and subtracted from C. The result is stored in C (C = C-(A+B)). A and B are added and subtracted from D. The result is stored in D (D = D-(A+B)).
In syntax-2, A, B, C are added and subtracted from D. The result is stored in E (E = D-(A+B+C))
In syntax-3, sub-group items within WS-GROUP1 and WS-GROUP2 are subtracted and the result is stored in WS-GROUP2.
Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-NUM1 PIC9(9)VALUE10.01 WS-NUM2 PIC9(9)VALUE10.01 WS-NUM3 PIC9(9)VALUE100.01 WS-NUM4 PIC9(9)VALUE100.01 WS-NUMA PIC9(9)VALUE10.01 WS-NUMB PIC9(9)VALUE10.01 WS-NUMC PIC9(9)VALUE10.01 WS-NUMD PIC9(9)VALUE100.01 WS-NUME PIC9(9)VALUE10.PROCEDUREDIVISION.SUBTRACT WS-NUM1 WS-NUM2 FROM WS-NUM3 WS-NUM4.SUBTRACT WS-NUMA WS-NUMB WS-NUMC FROM WS-NUMD GIVING WS-NUME.DISPLAY"WS-NUM1 : " WS-NUM1 DISPLAY"WS-NUM2 : " WS-NUM2 DISPLAY"WS-NUM3 : " WS-NUM3 DISPLAY"WS-NUM4 : " WS-NUM4 DISPLAY"WS-NUMA : " WS-NUMA DISPLAY"WS-NUMB : " WS-NUMB DISPLAY"WS-NUMC : " WS-NUMC DISPLAY"WS-NUMD : " WS-NUMD DISPLAY"WS-NUME : " WS-NUME STOPRUN.
JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLO
When you compile and execute the above program, it produces the following result −
WS-NUM1 : 000000010 WS-NUM2 : 000000010 WS-NUM3 : 000000080 WS-NUM4 : 000000080 WS-NUMA : 000000010 WS-NUMB : 000000010 WS-NUMC : 000000010 WS-NUMD : 000000100 WS-NUME : 000000070
Multiply Verb
Multiply verb is used for multiplication operations.
Syntax
Given below is the syntax to multiply two or more numbers −
MULTIPLY A BY B C MULTIPLY A BY B GIVING E
In syntax-1, A and B are multipled and the result is stored in B (B=A*B). A and C are multipled and the result is stored in C (C = A * C).
In syntax-2, A and B are multipled and the result is stored in E (E=A*B).
Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-NUM1 PIC9(9)VALUE10.01 WS-NUM2 PIC9(9)VALUE10.01 WS-NUM3 PIC9(9)VALUE10.01 WS-NUMA PIC9(9)VALUE10.01 WS-NUMB PIC9(9)VALUE10.01 WS-NUMC PIC9(9)VALUE10.PROCEDUREDIVISION.MULTIPLY WS-NUM1 BY WS-NUM2 WS-NUM3.MULTIPLY WS-NUMA BY WS-NUMB GIVING WS-NUMC.DISPLAY"WS-NUM1 : " WS-NUM1 DISPLAY"WS-NUM2 : " WS-NUM2 DISPLAY"WS-NUM3 : " WS-NUM3 DISPLAY"WS-NUMA : " WS-NUMA DISPLAY"WS-NUMB : " WS-NUMB DISPLAY"WS-NUMC : " WS-NUMC STOPRUN.
JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLO
When you compile and execute the above program, it produces the following result −
WS-NUM1 : 000000010 WS-NUM2 : 000000100 WS-NUM3 : 000000100 WS-NUMA : 000000010 WS-NUMB : 000000010 WS-NUMC : 000000100
Divide Verb
Divide verb is used for division operations.
Syntax
Given below is the syntax for division operations −
DIVIDE A INTO B DIVIDE A BY B GIVING C REMAINDER R
In syntax-1, B is divided by A and the result is stored in B (B=B/A).
In syntax-2, A is divided by B and the result is stored in C (C=A/B) and the remainder is stored in R.
Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-NUM1 PIC9(9)VALUE5.01 WS-NUM2 PIC9(9)VALUE250.01 WS-NUMA PIC9(9)VALUE100.01 WS-NUMB PIC9(9)VALUE15.01 WS-NUMC PIC9(9).01 WS-REM PIC9(9).PROCEDUREDIVISION.DIVIDE WS-NUM1 INTO WS-NUM2.DIVIDE WS-NUMA BY WS-NUMB GIVING WS-NUMC REMAINDER WS-REM.DISPLAY"WS-NUM1 : " WS-NUM1 DISPLAY"WS-NUM2 : " WS-NUM2 DISPLAY"WS-NUMA : " WS-NUMA DISPLAY"WS-NUMB : " WS-NUMB DISPLAY"WS-NUMC : " WS-NUMC DISPLAY"WS-REM : " WS-REM STOPRUN.
JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLO
When you compile and execute the above program, it produces the following result −
WS-NUM1 : 000000005 WS-NUM2 : 000000050 WS-NUMA : 000000100 WS-NUMB : 000000015 WS-NUMC : 000000006 WS-REM : 000000010
Compute Statement
Compute statement is used to write arithmetic expressions in COBOL. This is a replacement for Add, Subtract, Multiply, and Divide.
Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-NUM1 PIC9(9)VALUE10.01 WS-NUM2 PIC9(9)VALUE10.01 WS-NUM3 PIC9(9)VALUE10.01 WS-NUMA PIC9(9)VALUE50.01 WS-NUMB PIC9(9)VALUE10.01 WS-NUMC PIC9(9).PROCEDUREDIVISION.COMPUTE WS-NUMC=(WS-NUM1 * WS-NUM2)-(WS-NUMA / WS-NUMB)+ WS-NUM3.DISPLAY"WS-NUM1 : " WS-NUM1 DISPLAY"WS-NUM2 : " WS-NUM2 DISPLAY"WS-NUM3 : " WS-NUM3 DISPLAY"WS-NUMA : " WS-NUMA DISPLAY"WS-NUMB : " WS-NUMB DISPLAY"WS-NUMC : " WS-NUMC STOPRUN.
JCL to execute the above COBOL program.
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLO
When you compile and execute the above program, it produces the following result −
WS-NUM1 : 000000010 WS-NUM2 : 000000010 WS-NUM3 : 000000010 WS-NUMA : 000000050 WS-NUMB : 000000010 WS-NUMC : 000000105
COBOL – Data Layout
COBOL layout is the description of use of each field and the values present in it. Following are the data description entries used in COBOL −
- Redefines Clause
- Renames Clause
- Usage Clause
- Copybooks
Redefines Clause
Redefines clause is used to define a storage with different data description. If one or more data items are not used simultaneously, then the same storage can be utilized for another data item. So the same storage can be referred with different data items.
Syntax
Following is the syntax for Redefines clause −
01 WS-OLD PIC X(10). 01 WS-NEW1 REDEFINES WS-OLD PIC 9(8). 01 WS-NEW2 REDEFINES WS-OLD PIC A(10).
Following are the details of the used parameters −
- WS-OLD is Redefined Item
- WS-NEW1 and WS-NEW2 are Redefining Item
Level numbers of redefined item and redefining item must be the same and it cannot be 66 or 88 level number. Do not use VALUE clause with a redefining item. In File Section, do not use a redefines clause with 01 level number. Redefines definition must be the next data description you want to redefine. A redefining item will always have the same value as a redefined item.
Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-DESCRIPTION.05 WS-DATE1 VALUE'20140831'.10 WS-YEAR PICX(4).10 WS-MONTH PICX(2).10 WS-DATE PICX(2).05 WS-DATE2 REDEFINES WS-DATE1 PIC9(8).PROCEDUREDIVISION.DISPLAY"WS-DATE1 : "WS-DATE1.DISPLAY"WS-DATE2 : "WS-DATE2.STOPRUN.
JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLO
When you compile and execute the above program it produces the following result −
WS-DATE1 : 20140831 WS-DATE2 : 20140831
Renames Clause
Renames clause is used to give different names to existing data items. It is used to re-group the data names and give a new name to them. The new data names can rename across groups or elementary items. Level number 66 is reserved for renames.
Syntax
Following is the syntax for Renames clause −
01 WS-OLD. 10 WS-A PIC 9(12). 10 WS-B PIC X(20). 10 WS-C PIC A(25). 10 WS-D PIC X(12). 66 WS-NEW RENAMES WS-A THRU WS-C.
Renaming is possible at same level only. In the above example, WS-A, WS-B, and WS-C are at the same level. Renames definition must be the next data description you want to rename. Do not use Renames with 01, 77, or 66 level number. The data names used for renames must come in sequence. Data items with occur clause cannot be renamed.
Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-DESCRIPTION.05 WS-NUM.10 WS-NUM1 PIC9(2)VALUE20.10 WS-NUM2 PIC9(2)VALUE56.05 WS-CHAR.10 WS-CHAR1 PICX(2)VALUE'AA'.10 WS-CHAR2 PICX(2)VALUE'BB'.66 WS-RENAME RENAMES WS-NUM2 THRU WS-CHAR2.PROCEDUREDIVISION.DISPLAY"WS-RENAME : " WS-RENAME.STOPRUN.
JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLO
When you compile and execute the above program, it produces the following result −
WS-RENAME : 56AABB
Usage Clause
Usage clause specifies the operating system in which the format data is stored. It cannot be used with level numbers 66 or 88. If usage clause is specified on a group, then all the elementary items will have the same usage clause. The different options available with Usage clause are as follows −
Display
Data item is stored in ASCII format and each character will take 1 byte. It is default usage.
The following example calculates the number of bytes required −
01 WS-NUM PICS9(5)V9(3)USAGEISDISPLAY. It requires 8 bytes assignand decimal doesn't require any byte.01 WS-NUM PIC9(5)USAGEISDISPLAY. It requires 5 bytes assign.
COMPUTATIONAL / COMP
Data item is stored in binary format. Here, data items must be integer.
The following example calculates the number of bytes required −
01 WS-NUM PICS9(n)USAGEISCOMP.If'n'=1to4, it takes 2 bytes.If'n'=5to9, it takes 4 bytes.If'n'=10to18, it takes 8 bytes.
COMP-1
Data item is similar to Real or Float and is represented as a single precision floating point number. Internally, data is stored in hexadecimal format. COMP-1 does not accept PIC clause. Here 1 word is equal to 4 bytes.
COMP-2
Data item is similar to Long or Double and is represented as double precision floating point number. Internally, data is stored in hexadecimal format. COMP-2 does not specify PIC clause. Here 2 word is equal to 8 bytes.
COMP-3
Data item is stored in packed decimal format. Each digit occupies half a byte (1 nibble) and the sign is stored at the rightmost nibble.
The following example calculates the number of bytes required −
01 WS-NUM PIC9(n)USAGEISCOMP.Numberof bytes = n/2(If n is even)Numberof bytes = n/2+1(If n is odd, consider only integer part)01 WS-NUM PIC9(4)USAGEISCOMP-3VALUE21. It requires 2 bytes of storage as each digit occupies half a byte.01 WS-NUM PIC9(5)USAGEISCOMP-3VALUE21. It requires 3 bytes of storage as each digit occupies half a byte.
Copybooks
A COBOL copybook is a selection of code that defines data structures. If a particular data structure is used in many programs, then instead of writing the same data structure again, we can use copybooks. We use the COPY statement to include a copybook in a program. COPY statement is used in the WorkingStorage Section.
The following example includes a copybook inside a COBOL program −
DATADIVISION.WORKING-STORAGESECTION.COPY ABC.
Here ABC is the copybook name. The following data items in ABC copybook can be used inside a program.
01 WS-DESCRIPTION.05 WS-NUM.10 WS-NUM1 PIC9(2)VALUE20.10 WS-NUM2 PIC9(2)VALUE56.05 WS-CHAR.10 WS-CHAR1 PICX(2)VALUE'AA'.10 WS-CHAR2 PICX(2)VALUE'BB'.
COBOL – Conditional Statements
Conditional statements are used to change the execution flow depending on certain conditions specified by the programmer. Conditional statements will always evaluate to true or false. Conditions are used in IF, Evaluate, and Perform statements. The different types of conditions are as follows −
- IF Condition Statement
- Relation Condition
- Sign Condition
- Class Condition
- Condition-Name Condition
- Negated Condition
- Combined Condition
IF Condition Statement
IF statement checks for conditions. If a condition is true, the IF block is executed; and if the condition is false, the ELSE block is executed.
END-IF is used to end the IF block. To end the IF block, a period can be used instead of END-IF. But it is always preferable to use END-IF for multiple IF blocks.
Nested-IF − IF blocks appearing inside another IF block. There is no limit to the depth of nested IF statements.
Syntax
Following is the syntax of IF condition statements −
IF [condition] THEN [COBOL statements] ELSE [COBOL statements] END-IF.
Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-NUM1 PIC9(9).01 WS-NUM2 PIC9(9).01 WS-NUM3 PIC9(5).01 WS-NUM4 PIC9(6).PROCEDUREDIVISION. A000-FIRST-PARA.MOVE25TO WS-NUM1 WS-NUM3.MOVE15TO WS-NUM2 WS-NUM4.IF WS-NUM1 > WS-NUM2 THENDISPLAY'IN LOOP 1 - IF BLOCK'IF WS-NUM3 = WS-NUM4 THENDISPLAY'IN LOOP 2 - IF BLOCK'ELSEDISPLAY'IN LOOP 2 - ELSE BLOCK'END-IFELSEDISPLAY'IN LOOP 1 - ELSE BLOCK'END-IF.STOPRUN.
JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLO
When you compile and execute the above program, it produces the following result −
IN LOOP 1 - IF BLOCK IN LOOP 2 - ELSE BLOCK
Relation Condition
Relation condition compares two operands, either of which can be an identifier, literal, or arithmetic expression. Algebraic comparison of numeric fields is done regardless of size and usage clause.
For non-numeric operands
If two non-numeric operands of equal size are compared, then the characters are compared from left with the corresponding positions till the end is reached. The operand containing greater number of characters is declared greater.
If two non-numeric operands of unequal size are compared, then the shorter data item is appended with spaces at the end till the size of the operands becomes equal and then compared according to the rules mentioned in the previous point.
Syntax
Given below is the syntax of Relation condition statements −
[Data Name/Arithmetic Operation] [IS] [NOT] [Equal to (=),Greater than (>), Less than (<), Greater than or Equal (>=), Less than or equal (<=) ] [Data Name/Arithmetic Operation]
Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-NUM1 PIC9(9).01 WS-NUM2 PIC9(9).PROCEDUREDIVISION. A000-FIRST-PARA.MOVE25TO WS-NUM1.MOVE15TO WS-NUM2.IF WS-NUM1 ISGREATERTHANOREQUALTO WS-NUM2 THENDISPLAY'WS-NUM1 IS GREATER THAN WS-NUM2'ELSEDISPLAY'WS-NUM1 IS LESS THAN WS-NUM2'END-IF.STOPRUN.
JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLO
When you compile and execute the above program it produces the following result −
WS-NUM1 IS GREATER THAN WS-NUM2
Sign Condition
Sign condition is used to check the sign of a numeric operand. It determines whether a given numeric value is greater than, less than, or equal to ZERO.
Syntax
Following is the syntax of Sign condition statements −
[Data Name/Arithmetic Operation] [IS] [NOT] [Positive, Negative or Zero] [Data Name/Arithmetic Operation]
Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-NUM1 PICS9(9)VALUE-1234.01 WS-NUM2 PICS9(9)VALUE123456.PROCEDUREDIVISION. A000-FIRST-PARA.IF WS-NUM1 ISPOSITIVETHENDISPLAY'WS-NUM1 IS POSITIVE'.IF WS-NUM1 ISNEGATIVETHENDISPLAY'WS-NUM1 IS NEGATIVE'.IF WS-NUM1 ISZEROTHENDISPLAY'WS-NUM1 IS ZERO'.IF WS-NUM2 ISPOSITIVETHENDISPLAY'WS-NUM2 IS POSITIVE'.STOPRUN.
JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLO
When you compile and execute the above program it produces the following result −
WS-NUM1 IS NEGATIVE WS-NUM2 IS POSITIVE
Class Condition
Class condition is used to check if an operand contains only alphabets or numeric data. Spaces are considered in ALPHABETIC, ALPHABETIC-LOWER, and ALPHABETIC-UPPER.
Syntax
Following is the syntax of Class condition statements −
[Data Name/Arithmetic Operation>] [IS] [NOT] [NUMERIC, ALPHABETIC, ALPHABETIC-LOWER, ALPHABETIC-UPPER] [Data Name/Arithmetic Operation]
Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-NUM1 PICX(9)VALUE'ABCD '.01 WS-NUM2 PIC9(9)VALUE123456789.PROCEDUREDIVISION. A000-FIRST-PARA.IF WS-NUM1 ISALPHABETICTHENDISPLAY'WS-NUM1 IS ALPHABETIC'.IF WS-NUM1 ISNUMERICTHENDISPLAY'WS-NUM1 IS NUMERIC'.IF WS-NUM2 ISNUMERICTHENDISPLAY'WS-NUM2 IS NUMERIC'.STOPRUN.
JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLO
When you compile and execute the above program, it produces the following result −
WS-NUM1 IS ALPHABETIC WS-NUM2 IS NUMERIC
Condition-name Condition
A condition-name is a user-defined name. It contains a set of values specified by the user. It behaves like Boolean variables. They are defined with level number 88. It will not have a PIC clause.
Syntax
Following is the syntax of user-defined condition statements −
88 [Condition-Name] VALUE [IS, ARE] [LITERAL] [THRU LITERAL].
Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-NUM PIC9(3).88 PASS VALUESARE041THRU100.88 FAIL VALUESARE000THRU40.PROCEDUREDIVISION. A000-FIRST-PARA.MOVE65TO WS-NUM.IF PASSDISPLAY'Passed with ' WS-NUM ' marks'.IF FAIL DISPLAY'FAILED with ' WS-NUM 'marks'.STOPRUN.</pre>JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLOWhen you compile and execute the above program, it produces the following result −
Passed with 065 marksNegated Condition
Negated condition is given by using the NOT keyword. If a condition is true and we have given NOT in front of it, then its final value will be false.
Syntax
Following is the syntax of Negated condition statements −
IF NOT [CONDITION] COBOL Statements END-IF.Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-NUM1 PIC9(2)VALUE20.01 WS-NUM2 PIC9(9)VALUE25.PROCEDUREDIVISION. A000-FIRST-PARA.IFNOT WS-NUM1 ISLESSTHAN WS-NUM2 THENDISPLAY'IF-BLOCK'ELSEDISPLAY'ELSE-BLOCK'END-IF.STOPRUN.JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLOWhen you compile and execute the above program, it produces the following result −
ELSE-BLOCKCombined Condition
A combined condition contains two or more conditions connected using logical operators AND or OR.
Syntax
Following is the syntax of combined condition statements −
IF [CONDITION] AND [CONDITION] COBOL Statements END-IF.Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-NUM1 PIC9(2)VALUE20.01 WS-NUM2 PIC9(2)VALUE25.01 WS-NUM3 PIC9(2)VALUE20.PROCEDUREDIVISION. A000-FIRST-PARA.IF WS-NUM1 ISLESSTHAN WS-NUM2 AND WS-NUM1=WS-NUM3 THENDISPLAY'Both condition OK'ELSEDISPLAY'Error'END-IF.STOPRUN.JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLOWhen you compile and execute the above program, it produces the following result −
Both condition OKEvaluate Verb
Evaluate verb is a replacement of series of IF-ELSE statement. It can be used to evaluate more than one condition. It is similar to SWITCH statement in C programs.
Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-A PIC9VALUE0.PROCEDUREDIVISION.MOVE3TO WS-A.EVALUATETRUEWHEN WS-A >2DISPLAY'WS-A GREATER THAN 2'WHEN WS-A <0DISPLAY'WS-A LESS THAN 0'WHENOTHERDISPLAY'INVALID VALUE OF WS-A'END-EVALUATE.STOPRUN.JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLOWhen you compile and execute the above program, it produces the following result −
WS-A GREATER THAN 2COBOL - Loop Statements
There are some tasks that need to be done over and over again like reading each record of a file till its end. The loop statements used in COBOL are −
- Perform Thru
- Perform Until
- Perform Times
- Perform Varying
Perform Thru
Perform Thru is used to execute a series of paragraph by giving the first and last paragraph names in the sequence. After executing the last paragraph, the control is returned back.
In-line Perform
Statements inside the PERFORM will be executed till END-PERFORM is reached.
Syntax
Following is the syntax of In-line perform −
PERFORM DISPLAY 'HELLO WORLD' END-PERFORM.
Out-of-line Perform
Here, a statement is executed in one paragraph and then the control is transferred to other paragraph or section.
Syntax
Following is the syntax of Out-of-line perform −
PERFORM PARAGRAPH1 THRU PARAGRAPH2
Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.PROCEDUREDIVISION. A-PARA.PERFORMDISPLAY'IN A-PARA'END-PERFORM.PERFORM C-PARA THRU E-PARA. B-PARA.DISPLAY'IN B-PARA'.STOPRUN. C-PARA.DISPLAY'IN C-PARA'. D-PARA.DISPLAY'IN D-PARA'. E-PARA.DISPLAY'IN E-PARA'.
JCL to execute the above COBOL program.
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLO
When you compile and execute the above program, it produces the following result −
IN A-PARA IN C-PARA IN D-PARA IN E-PARA IN B-PARA
Perform Until
In perform until, a paragraph is executed until the given condition becomes true. With test before is the default condition and it indicates that the condition is checked before the execution of statements in a paragraph.
Syntax
Following is the syntax of perform until −
PERFORM A-PARA UNTILCOUNT=5PERFORM A-PARA WITHTESTBEFOREUNTILCOUNT=5PERFORM A-PARA WITHTESTAFTERUNTILCOUNT=5
Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-CNT PIC9(1)VALUE0.PROCEDUREDIVISION. A-PARA.PERFORM B-PARA WITHTESTAFTERUNTIL WS-CNT>3.STOPRUN. B-PARA.DISPLAY'WS-CNT : 'WS-CNT.ADD1TO WS-CNT.
JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLO
When you compile and execute the above program, it produces the following result −
WS-CNT : 0 WS-CNT : 1 WS-CNT : 2 WS-CNT : 3
Perform Times
In perform times, a paragraph will be executed the number of times specified.
Syntax
Following is the syntax of perform times −
PERFORM A-PARA 5 TIMES.
Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.PROCEDUREDIVISION. A-PARA.PERFORM B-PARA 3TIMES.STOPRUN. B-PARA.DISPLAY'IN B-PARA'.
JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLO
When you compile and execute the above program, it produces the following result −
IN B-PARA IN B-PARA IN B-PARA
Perform Varying
In perform varying, a paragraph will be executed till the condition in Until phrase becomes true.
Syntax
Following is the syntax of perform varying −
PERFORM A-PARA VARYING A FROM 1 BY 1 UNTIL A = 5.
Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-A PIC9VALUE0.PROCEDUREDIVISION. A-PARA.PERFORM B-PARA VARYING WS-A FROM1BY1UNTIL WS-A=5STOPRUN. B-PARA.DISPLAY'IN B-PARA ' WS-A.
JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLO
When you compile and execute the above program, it produces the following result −
IN B-PARA 1 IN B-PARA 2 IN B-PARA 3 IN B-PARA 4
GO TO Statement
GO TO statement is used to change the flow of execution in a program. In GO TO statements, transfer goes only in the forward direction. It is used to exit a paragraph. The different types of GO TO statements used are as follows −
Unconditional GO TO
GO TO para-name.
Conditional GO TO
GO TO para-1 para-2 para-3 DEPENDING ON x.
If 'x' is equal to 1, then the control will be transferred to the first paragraph; and if 'x' is equal to 2, then the control will be transferred to the second paragraph, and so on.
Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-A PIC9VALUE2.PROCEDUREDIVISION. A-PARA.DISPLAY'IN A-PARA'GOTO B-PARA. B-PARA.DISPLAY'IN B-PARA '.GOTO C-PARA D-PARA DEPENDINGON WS-A. C-PARA.DISPLAY'IN C-PARA '. D-PARA.DISPLAY'IN D-PARA '.STOPRUN.
JCL to execute the above COBOL program:
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLO
When you compile and execute the above program, it produces the following result:
IN A-PARA IN B-PARA IN D-PARA
COBOL - String Handling
String handling statements in COBOL are used to do multiple functional operations on strings. Following are the string handling statements −
- Inspect
- String
- Unstring
Inspect
Inspect verb is used to count or replace the characters in a string. String operations can be performed on alphanumeric, numeric, or alphabetic values. Inspect operations are performed from left to right. The options used for the string operations are as follows −
Tallying
Tallying option is used to count the string characters.
Syntax
Following is the syntax of Tallying option −
INSPECT input-string TALLYING output-count FOR ALL CHARACTERS
The parameters used are −
- input-string − The string whose characters are to be counted.
- output-count − Data item to hold the count of characters.
Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-CNT1 PIC9(2)VALUE0.01 WS-CNT2 PIC9(2)VALUE0.01 WS-STRING PICX(15)VALUE'ABCDACDADEAAAFF'.PROCEDUREDIVISION.INSPECT WS-STRING TALLYING WS-CNT1 FORCHARACTER.DISPLAY"WS-CNT1 : "WS-CNT1.INSPECT WS-STRING TALLYING WS-CNT2 FORALL'A'.DISPLAY"WS-CNT2 : "WS-CNT2 STOPRUN.
JCL to execute the above COBOL program.
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLO
When you compile and execute the above program, it produces the following result −
WS-CNT1 : 15 WS-CNT2 : 06
Replacing
Replacing option is used to replace the string characters.
Syntax
Following is the syntax of Replacing option −
INSPECT input-string REPLACING ALL char1 BY char2.
The parameter used is −
- input-string − The string whose characters are to be replaced from char1 to char2.
Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-STRING PICX(15)VALUE'ABCDACDADEAAAFF'.PROCEDUREDIVISION.DISPLAY"OLD STRING : "WS-STRING.INSPECT WS-STRING REPLACINGALL'A'BY'X'.DISPLAY"NEW STRING : "WS-STRING.STOPRUN.
JCL to execute the above COBOL program.
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLO
When you compile and execute the above program, it produces the following result −
OLD STRING : ABCDACDADEAAAFF NEW STRING : XBCDXCDXDEXXXFF
String
String verb is used to concatenate the strings. Using STRING statement, two or more strings of characters can be combined to form a longer string. Delimited By clause is compulsory.
Syntax
Following is the syntax of String verb −
STRING ws-string1 DELIMITEDBYSPACE ws-string2 DELIMITEDBYSIZEINTO ws-destination-string WITHPOINTER ws-count ONOVERFLOWDISPLAY message1 NOTONOVERFLOWDISPLAY message2 END-STRING.
Following are the details of the used parameters −
- ws-string1 and ws-string2 : Input strings to be concatenated
- ws-string : Output string
- ws-count : Used to count the length of new concatenated string
- Delimited specifies the end of string
- Pointer and Overflow are optional
Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-STRING PICA(30).01 WS-STR1 PICA(15)VALUE'Tutorialspoint'.01 WS-STR2 PICA(7)VALUE'Welcome'.01 WS-STR3 PICA(7)VALUE'To AND'.01 WS-COUNT PIC99VALUE1.PROCEDUREDIVISION.STRING WS-STR2 DELIMITEDBYSIZEWS-STR3 DELIMITEDBYSPACE WS-STR1 DELIMITEDBYSIZEINTO WS-STRING WITHPOINTER WS-COUNT ONOVERFLOWDISPLAY'OVERFLOW!'END-STRING.DISPLAY'WS-STRING : 'WS-STRING.DISPLAY'WS-COUNT : 'WS-COUNT.STOPRUN.</pre>JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLOWhen you compile and execute the above program, it produces the following result −
WS-STRING : WelcomeToTutorialspoint WS-COUNT : 25Unstring
Unstring verb is used to split one string into multiple sub-strings. Delimited By clause is compulsory.
Syntax
Following is the syntax of Unstring verb −
UNSTRING ws-string DELIMITEDBYSPACEINTO ws-str1, ws-str2 WITHPOINTER ws-count ONOVERFLOWDISPLAYmessageNOTONOVERFLOWDISPLAYmessageEND-UNSTRING.Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-STRING PICA(30)VALUE'WELCOME TO TUTORIALSPOINT'.01 WS-STR1 PICA(7).01 WS-STR2 PICA(2).01 WS-STR3 PICA(15).01 WS-COUNT PIC99VALUE1.PROCEDUREDIVISION.UNSTRING WS-STRING DELIMITEDBYSPACEINTO WS-STR1, WS-STR2, WS-STR3 END-UNSTRING.DISPLAY'WS-STR1 : 'WS-STR1.DISPLAY'WS-STR2 : 'WS-STR2.DISPLAY'WS-STR3 : 'WS-STR3.STOPRUN.JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLOWhen you compile and execute the above program, it produces the following result −
WS-STR1 : WELCOME WS-STR2 : TO WS-STR3 : TUTORIALSPOINTCOBOL - Table Processing
Arrays in COBOL are known as tables. An array is a linear data structure and is a collection of individual data items of same type. Data items of a table are internally sorted.
Table Declaration
Table is declared in Data Division. Occurs clause is used to define a table. Occurs clause indicates the repetition of data name definition. It can be used only with level numbers starting from 02 to 49. Do not use occurs clause with Redefines. Description of one-dimensional and two-dimensional table is as follows −
One-Dimensional Table
In a one-dimensional table, occurs clause is used only once in declaration. WSTABLE is the group item that contains table. WS-B names the table elements that occur 10 times.
Syntax
Following is the syntax for defining a one-dimensional table −
01 WS-TABLE. 05 WS-A PIC A(10) OCCURS 10 TIMES.Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-TABLE.05 WS-A PICA(10)VALUE'TUTORIALS'OCCURS5TIMES.PROCEDUREDIVISION.DISPLAY"ONE-D TABLE : "WS-TABLE.STOPRUN.JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLOWhen you compile and execute the above program, it produces the following result −
ONE-D TABLE : TUTORIALS TUTORIALS TUTORIALS TUTORIALS TUTORIALSTwo-Dimensional Table
A two-dimensional table is created with both data elements being variable length. For reference, go through the syntax and then try to analyze the table. The first array (WS-A) can occur from 1 to 10 times and the inner array (WS-C) can occur from 1 to 5 times. For each entry of WS-A, there will be corresponding 5 entries of WS-C.
Syntax
Following is the syntax for defining a two-dimensional table −
01 WS-TABLE. 05 WS-A OCCURS 10 TIMES.10 WS-B PIC A(10). 10 WS-C OCCURS 5 TIMES. 15 WS-D PIC X(6).Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-TABLE.05 WS-A OCCURS2TIMES.10 WS-B PICA(10)VALUE' TUTORIALS'.10 WS-C OCCURS2TIMES.15 WS-D PICX(6)VALUE' POINT'.PROCEDUREDIVISION.DISPLAY"TWO-D TABLE : "WS-TABLE.STOPRUN.JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLOWhen you compile and execute the above program, it produces the following result −
TWO-D TABLE : TUTORIALS POINT POINT TUTORIALS POINT POINTSubscript
Table individual elements can be accessed by using subscript. Subscript values can range from 1 to the number of times the table occurs. A subscript can be any positive number. It does not require any declaration in data division. It is automatically created with occurs clause.
Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-TABLE.05 WS-A OCCURS3TIMES.10 WS-B PICA(2).10 WS-C OCCURS2TIMES.15 WS-D PICX(3).PROCEDUREDIVISION.MOVE'12ABCDEF34GHIJKL56MNOPQR'TO WS-TABLE.DISPLAY'WS-TABLE : ' WS-TABLE.DISPLAY'WS-A(1) : ' WS-A(1).DISPLAY'WS-C(1,1) : ' WS-C(1,1).DISPLAY'WS-C(1,2) : ' WS-C(1,2).DISPLAY'WS-A(2) : ' WS-A(2).DISPLAY'WS-C(2,1) : ' WS-C(2,1).DISPLAY'WS-C(2,2) : ' WS-C(2,2).DISPLAY'WS-A(3) : ' WS-A(3).DISPLAY'WS-C(3,1) : ' WS-C(3,1).DISPLAY'WS-C(3,2) : ' WS-C(3,2).STOPRUN.JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLOWhen you compile and execute the above program, it produces the following result −
WS-TABLE : 12ABCDEF34GHIJKL56MNOPQR WS-A(1) : 12ABCDEF WS-C(1,1) : ABC WS-C(1,2) : DEF WS-A(2) : 34GHIJKL WS-C(2,1) : GHI WS-C(2,2) : JKL WS-A(3) : 56MNOPQR WS-C(3,1) : MNO WS-C(3,2) : PQRIndex
Table elements can also be accessed using index. An index is a displacement of element from the start of the table. An index is declared with Occurs clause using INDEXED BY clause. The value of index can be changed using SET statement and PERFORM Varying option.
Syntax
Following is the syntax for defining Index in a table −
01 WS-TABLE. 05 WS-A PIC A(10) OCCURS 10 TIMES INDEXED BY I.Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-TABLE.05 WS-A OCCURS3TIMESINDEXEDBY I.10 WS-B PICA(2).10 WS-C OCCURS2TIMESINDEXEDBY J.15 WS-D PICX(3).PROCEDUREDIVISION.MOVE'12ABCDEF34GHIJKL56MNOPQR'TO WS-TABLE.PERFORM A-PARA VARYING I FROM1BY1UNTIL I >3STOPRUN. A-PARA.PERFORM C-PARA VARYING J FROM1BY1UNTIL J>2. C-PARA.DISPLAY WS-C(I,J).JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLOWhen you compile and execute the above program, it produces the following result −
ABC DEF GHI JKL MNO PQRSet Statement
Set statement is used to change the index value. Set verb is used to initialize, increment, or decrement the index value. It is used with Search and Search All to locate elements in table.
Syntax
Following is the syntax for using a Set statement −
SET I J TO positive-number SET I TO J SET I TO 5 SET I J UP BY 1 SET J DOWN BY 5Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-TABLE.05 WS-A OCCURS3TIMESINDEXEDBY I.10 WS-B PICA(2).10 WS-C OCCURS2TIMESINDEXEDBY J.15 WS-D PICX(3).PROCEDUREDIVISION.MOVE'12ABCDEF34GHIJKL56MNOPQR'TO WS-TABLE.SET I J TO1.DISPLAY WS-C(I,J).SET I J UPBY1.DISPLAY WS-C(I,J).STOPRUN.JCL to execute the above COBOL program.
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLOWhen you compile and execute the above program, it produces the following result −
ABC JKLSearch
Search is a linear search method, which is used to find elements inside the table. It can be performed on sorted as well as unsorted table. It is used only for tables declared by Index phrase. It starts with the initial value of index. If the searched element is not found, then the index is automatically incremented by 1 and it continues till the end of table.
Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-TABLE.05 WS-A PICX(1)OCCURS18TIMESINDEXEDBY I.01 WS-SRCH PICA(1)VALUE'M'.PROCEDUREDIVISION.MOVE'ABCDEFGHIJKLMNOPQR'TO WS-TABLE.SET I TO1.SEARCH WS-AATENDDISPLAY'M NOT FOUND IN TABLE'WHEN WS-A(I)= WS-SRCH DISPLAY'LETTER M FOUND IN TABLE'END-SEARCH.STOPRUN.</pre>JCL to execute the above COBOL program.
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLOWhen you compile and execute the above program, it produces the following result −
LETTER M FOUND IN TABLESearch All
Search All is a binary search method, which is used to find elements inside the table. Table must be in sorted order for Search All option. The index does not require initialization. In binary search, the table is divided into two halves and it determines in which half the searched element is present. This process repeats till the element is found or the end is reached.
Example
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION.01 WS-TABLE.05 WS-RECORD OCCURS10TIMESASCENDINGKEYIS WS-NUM INDEXEDBY I.10 WS-NUM PIC9(2).10 WS-NAME PICA(3).PROCEDUREDIVISION.MOVE'12ABC56DEF34GHI78JKL93MNO11PQR'TO WS-TABLE.SEARCHALL WS-RECORDATENDDISPLAY'RECORD NOT FOUND'WHEN WS-NUM(I)=93DISPLAY'RECORD FOUND 'DISPLAY WS-NUM(I)DISPLAY WS-NAME(I)END-SEARCH.</pre>JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLOWhen you compile and execute the above program, it produces the following result −
RECORD FOUND 93 MNOCOBOL - File Handling
The concept of files in COBOL is different from that in C/C++. While learning the basics of 'File' in COBOL, the concepts of both languages should not be corelated. Simple text files cannot be used in COBOL, instead PS (Physical Sequential) and VSAM files are used. PS files will be discussed in this module.
To understand file handling in COBOL, one must know the basic terms. These terms only serve to understand the fundamentals of file handling. Further in depth terminology would be discussed in the chapter 'File Handling Verbs'. Following are the basic terms −
- Field
- Record
- Physical Record
- Logical Record
- File
The following example helps in understanding these terms −
Field
Field is used to indicate the data stored about an element. It represents a single element as shown in the above example such as student id, name, marks, total marks, and percentage. The number of characters in any field is known as field size, for example, student name can have 10 characters. Fields can have the following attributes −
- Primary keys are those fields that are unique to each record and are used to identify a particular record. For example, in students marks file, each student will be having a unique student id which forms the primary key.
- Secondary keys are unique or non-unique fields that are used to search for related data. For example, in students marks file, full name of student can be used as secondary key when student id is not known.
- Descriptors fields are used to describe an entity. For example, in students marks file, marks and percentage fields that add meaning to the record are known descriptors.
Record
Record is a collection of fields that is used to describe an entity. One or more fields together form a record. For example, in students marks file, student id, name, marks, total marks, and percentage form one record. The cumulative size of all the fields in a record is known as the record size. The records present in a file may be of fixed length or variable length.
Physical Record
Physical record is the information that exists on the external device. It is also known as a block.
Logical Record
Logical record is the information used by the program. In COBOL programs, only one record can be handled at any point of time and it is called as logical record.
File
File is a collection of related records. For example, the students marks file consists of records of all the students.
COBOL - File Organization
File organization indicates how the records are organized in a file. There are different types of organizations for files so as to increase their efficiency of accessing the records. Following are the types of file organization schemes −
- Sequential file organization
- Indexed sequential file organization
- Relative file organization
The syntaxes in this module, mentioned along with their respective terms, only refer to their usage in the program. The complete programs using these syntaxes would be discussed in the chapter 'File handling Verbs'.
Sequential File Organization
A sequential file consists of records that are stored and accessed in sequential order. Following are the key attributes of sequential file organization −
- Records can be read in sequential order. For reading the 10th record, all the previous 9 records should be read.
- Records are written in sequential order. A new record cannot be inserted in between. A new record is always inserted at the end of the file.
- After placing a record into a sequential file, it is not possible to delete, shorten, or lengthen a record.
- Order of the records, once inserted, can never be changed.
- Updation of record is possible. A record can be overwritten, if the new record length is same as the old record length.
- Sequential output files are good option for printing.
Syntax
Following is the syntax of sequential file organization −
INPUT-OUTPUT SECTION. FILE-CONTROL. SELECT file-name ASSIGN TO dd-name-jcl ORGANIZATION IS SEQUENTIAL
Indexed Sequential File Organization
An indexed sequential file consists of records that can be accessed sequentially. Direct access is also possible. It consists of two parts −
- Data File contains records in sequential scheme.
- Index File contains the primary key and its address in the data file.
Following are the key attributes of sequential file organization −
- Records can be read in sequential order just like in sequential file organization.
- Records can be accessed randomly if the primary key is known. Index file is used to get the address of a record and then the record is fetched from the data file.
- Sorted index is maintained in this file system which relates the key value to the position of the record in the file.
- Alternate index can also be created to fetch the records.
Syntax
Following is the syntax of indexed sequential file organization −
INPUT-OUTPUTSECTION.FILE-CONTROL.SELECT file-name ASSIGNTO dd-name-jcl ORGANIZATIONISINDEXEDRECORDKEYIS primary-key ALTERNATERECORDKEYIS rec-key
Relative File Organization
A relative file consists of records ordered by their relative address. Following are the key attributes of relative file organization −
- Records can be read in sequential order just like in sequential and indexed file organization.
- Records can be accessed using relative key. Relative key represents the records location relative to the address of the start of the file.
- Records can be inserted using relative key. Relative address is calculated using relative key.
- Relative file provides the fastest access to the records.
- The main disadvantage of this file system is that if some intermediate records are missing, they will also occupy space.
Syntax
Following is the syntax of relative file organization −
INPUT-OUTPUTSECTION.FILE-CONTROL.SELECT file-name ASSIGNTO dd-name-jcl ORGANIZATIONISRELATIVERELATIVEKEYIS rec-key
COBOL - File Access Mode
Till now, file organization schemes have been discussed. For each file organization scheme, different access modes can be used. Following are the types of file access modes −
- Sequential Access
- Random Access
- Dynamic Access
The syntaxes in this module, mentioned along with their respective terms, only refer to their usage in the program. The complete programs using these syntaxes would be discussed in the next chapter.
Sequential Access
When the access mode is sequential, the method of record retrieval changes as per the selected file organization.
- For sequential files, records are accessed in the same order in which they were inserted.
- For indexed files, the parameter used to fetch the records are the record key values.
- For relative files, relative record keys are used to retrieve the records.
Syntax
Following is the syntax of sequential access mode −
ENVIRONMENT DIVISION. INPUT-OUTPUT SECTION. FILE-CONTROL. SELECT file-name ASSIGN TO dd-name ORGANIZATION IS SEQUENTIAL ACCESS MODE IS SEQUENTIAL ENVIRONMENT DIVISION. INPUT-OUTPUT SECTION. FILE-CONTROL. SELECT file-name ASSIGN TO dd-name ORGANIZATION IS INDEXED ACCESS MODE IS SEQUENTIAL RECORD KEY IS rec-key1 ALTERNATE RECORD KEY IS rec-key2 ENVIRONMENT DIVISION. INPUT-OUTPUT SECTION. FILE-CONTROL. SELECT file-name ASSIGN TO dd-name ORGANIZATION IS RELATIVE ACCESS MODE IS SEQUENTIAL RELATIVE KEY IS rec-key1
Random Access
When the access mode is RANDOM, the method of record retrieval changes as per the selected file organization.
- For indexed files, records are accessed according to the value placed in a key field which can be primary or alternate key. There can be one or more alternate indexes.
- For relative files , records are retrieved through relative record keys.
Syntax
Following is the syntax of random access mode −
ENVIRONMENT DIVISION. INPUT-OUTPUT SECTION. FILE-CONTROL. SELECT file-name ASSIGN TO dd-name ORGANIZATION IS INDEXED ACCESS MODE IS RANDOM RECORD KEY IS rec-key1 ALTERNATE RECORD KEY IS rec-key2 ENVIRONMENT DIVISION. INPUT-OUTPUT SECTION. FILE-CONTROL. SELECT file-name ASSIGN TO dd-name ORGANIZATION IS RELATIVE ACCESS MODE IS RANDOM RELATIVE KEY IS rec-key1
Dynamic Access
Dynamic access supports both sequential and random access in the same program. With dynamic access, one file definition is used to perform both sequential and random processing like accessing some records in sequential order and other records by their keys.
With relative and indexed files, the dynamic access mode allows you to switch back and forth between sequential access mode and random access mode while reading a file by using the NEXT phrase on the READ statement. NEXT and READ functionalities will be discussed in the next chapter.
Syntax
Following is the syntax of dynamic access mode −
ENVIRONMENT DIVISION. INPUT-OUTPUT SECTION. FILE-CONTROL. SELECT file-name ASSIGN TO dd-name ORGANIZATION IS SEQUENTIAL ACCESS MODE IS DYNAMIC RECORD KEY IS rec-key1 ALTERNATE RECORD KEY IS rec-key2 ENVIRONMENT DIVISION. INPUT-OUTPUT SECTION. FILE-CONTROL. SELECT file-name ASSIGN TO dd-name ORGANIZATION IS RELATIVE ACCESS MODE IS DYNAMIC RELATIVE KEY IS rec-key1
COBOL - File Handling Verbs
File handling verbs are used to perform various operations on files. Following are the file handling verbs −
- Open
- Read
- Write
- Rewrite
- Delete
- Start
- Close
Open Verb
Open is the first file operation that must be performed. If Open is successful, then only further operations are possible on a file. Only after opening a file, the variables in the file structure are available for processing. FILE STATUS variable is updated after each file operation.
Syntax
OPEN "mode" file-name.
Here, file-name is string literal, which you will use to name your file. A file can be opened in the following modes −
| Sr.No. | Mode & Description |
|---|---|
| 1 | InputInput mode is used for existing files. In this mode, we can only read the file, no other operations are allowed on the file. |
| 2 | OutputOutput mode is used to insert records in files. If a sequential file is used and the file is holding some records, then the existing records will be deleted first and then new records will be inserted in the file. It will not happen so in case of an indexed file or a relative file. |
| 3 | ExtendExtend mode is used to append records in a sequential file. In this mode, records are inserted at the end. If file access mode is Random or Dynamic, then extend mode cannot be used. |
| 4 | I-OInput-Output mode is used to read and rewrite the records of a file. |
Read Verb
Read verb is used to read the file records. The function of read is to fetch records from a file. At each read verb, only one record can be read into the file structure. To perform a read operation, open the file in INPUT or I-O mode. At each read statement, the file pointer is incremented and hence the successive records are read.
Syntax
Following is the syntax to read the records when the file access mode is sequential −
READ file-name NEXT RECORD INTO ws-file-structure AT END DISPLAY 'End of File' NOT AT END DISPLAY 'Record Details:' ws-file-structure END-READ.
Following are the parameters used −
- NEXT RECORD is optional and is specified when an indexed sequential file is being read sequentially.
- INTO clause is optional. ws-file-structure is defined in the WorkingStorage Section to get the values from the READ statement.
- AT END condition becomes True when the end of file is reached.
Example − The following example reads an existing file using line sequential organization. This program can be compiled and executed using Live Demo option where it will display all the records present in the file.
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.ENVIRONMENTDIVISION.INPUT-OUTPUTSECTION.FILE-CONTROL.SELECT STUDENT ASSIGNTO'input.txt'ORGANIZATIONISLINESEQUENTIAL.DATADIVISION.FILESECTION.FD STUDENT.01 STUDENT-FILE.05 STUDENT-ID PIC9(5).05 NAME PICA(25).WORKING-STORAGESECTION.01 WS-STUDENT.05 WS-STUDENT-ID PIC9(5).05 WS-NAME PICA(25).01 WS-EOF PICA(1).PROCEDUREDIVISION.OPENINPUT STUDENT.PERFORMUNTIL WS-EOF='Y'READ STUDENT INTO WS-STUDENTATENDMOVE'Y'TO WS-EOF NOTATENDDISPLAY WS-STUDENT END-READEND-PERFORM.CLOSE STUDENT.STOPRUN.</pre>Suppose the input file data available in the input.txt file contains the following −
20003 Mohtashim M. 20004 Nishant Malik 20005 Amitabh BachhanWhen you compile and execute the above program, it produces the following result −
20003 Mohtashim M. 20004 Nishant Malik 20005 Amitabh BachhanSyntax
Following is the syntax to read a record when the file access mode is random −
READ file-name RECORD INTO ws-file-structure KEY IS rec-key INVALID KEY DISPLAY 'Invalid Key' NOT INVALID KEY DISPLAY 'Record Details: ' ws-file-structure END-READ.Example − The following example reads an existing file using indexed organization. This program can be compiled and executed using JCL on Mainframes where it will display all the records present in the file. On Mainframes server, we do not use text files; instead we use PS files.
Let's assume that the file present on Mainframes have same content as input.txt file in the above example.
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.ENVIRONMENTDIVISION.INPUT-OUTPUTSECTION.FILE-CONTROL.SELECT STUDENT ASSIGNTO IN1ORGANIZATIONISINDEXEDACCESSISRANDOMRECORDKEYIS STUDENT-ID FILESTATUSIS FS.DATADIVISION.FILESECTION.FD STUDENT.01 STUDENT-FILE.05 STUDENT-ID PIC9(5).05 NAME PICA(25).WORKING-STORAGESECTION.01 WS-STUDENT.05 WS-STUDENT-ID PIC9(5).05 WS-NAME PICA(25).PROCEDUREDIVISION.OPENINPUT STUDENT.MOVE20005TO STUDENT-ID.READ STUDENT RECORDINTO WS-STUDENT-FILE KEYIS STUDENT-ID INVALIDKEYDISPLAY'Invalid Key'NOTINVALIDKEYDISPLAY WS-STUDENT-FILE END-READ.CLOSE STUDENT.STOPRUN.</pre>JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLO //IN1 DD DSN = STUDENT-FILE-NAME,DISP=SHRWhen you compile and execute the above program, it produces the following result −
20005 Amitabh BachhanWrite Verb
Write verb is used to insert records in a file. Once the record is written, it is no longer available in the record buffer. Before inserting records into the file, move the values into the record buffer and then perform write verb.
Write statement can be used with FROM option to directly write records from the working storage variables. From is an optional clause. If the access mode is sequential, then to write a record, the file must open in Output mode or Extend mode. If the access mode is random or dynamic, then to write a record, the file must open in Output mode or I-O mode.
Syntax
Following is the syntax to read a record when the file organization is sequential −
WRITE record-buffer [FROM ws-file-structure] END-WRITE.Following is the syntax to read a record when the file organization is indexed or relative −
WRITE record-buffer [FROM ws-file-structure] INVALID KEY DISPLAY 'Invalid Key' NOT INVALID KEY DISPLAY 'Record Inserted' END-WRITE.Example − The following example shows how to insert a new record in a new file when the organization is sequential.
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.ENVIRONMENTDIVISION.INPUT-OUTPUTSECTION.FILE-CONTROL.SELECT STUDENT ASSIGNTO OUT101 STUDENT-FILE.05 STUDENT-ID PIC9(5).05 NAME PICA(25).05CLASSPICX(3).WORKING-STORAGESECTION.01 WS-STUDENT.05 WS-STUDENT-ID PIC9(5).05 WS-NAME PICA(25).05 WS-CLASS PICX(3).PROCEDUREDIVISION.OPENEXTEND STUDENT.MOVE1000TO STUDENT-ID.MOVE'Tim'TO NAME.MOVE'10'TOCLASS.WRITE STUDENT-FILEORGANIZATIONISSEQUENTIALACCESSISSEQUENTIALFILESTATUSIS FS.DATADIVISION.FILESECTION.FD STUDENTEND-WRITE.CLOSE STUDENT.STOPRUN.</pre>JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLO //OUT1 DD DSN = OUTPUT-FILE-NAME,DISP =(NEW,CATALOG,DELETE)When you compile and execute the above program, it will add a new record to the output file.
1000 Tim 10Rewrite Verb
Rewrite verb is used to update the records. File should be opened in I-O mode for rewrite operations. It can be used only after a successful Read operation. Rewrite verb overwrites the last record read.
Syntax
Following is the syntax to read a record when the file organization is sequential −
REWRITE record-buffer [FROM ws-file-structure] END-REWRITE.Following is the syntax to read a record when the file organization is indexed or relative −
REWRITE record-buffer [FROM ws-file-structure] INVALID KEY DISPLAY 'Invalid Key' NOT INVALID KEY DISPLAY 'Record Updated' END-REWRITE.Example − The following example shows how to update an existing record which we have inserted in the previous Write step −
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.ENVIRONMENTDIVISION.INPUT-OUTPUTSECTION.FILE-CONTROL.SELECT STUDENT ASSIGNTO IN101 STUDENT-FILE.05 STUDENT-ID PIC9(4).05 NAME PICA(12).05CLASSPICX(3).WORKING-STORAGESECTION.01 WS-STUDENT.05 WS-STUDENT-ID PIC9(5).05 WS-NAME PICA(25).05 WS-CLASS PICX(3).PROCEDUREDIVISION.OPENI-O STUDENT.MOVE'1000'TO STUDENT-ID.READ STUDENTORGANIZATIONISINDEXEDACCESSISRANDOMRECORDKEYIS STUDENT-ID FILESTATUSIS FS.DATADIVISION.FILESECTION.FD STUDENTEND-READ.MOVE'Tim Dumais'TO NAME.REWRITE STUDENT-FILE END-REWRITE.CLOSE STUDENT.STOPRUN.KEYIS STUDENT-ID INVALIDKEYDISPLAYKEYISNOT EXISTINGJCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLO //IN1 DD DSN = OUTPUT-FILE-NAME,DISP = SHRWhen you compile and execute the above program, it will update the record −
1000 Tim Dumais 10Delete Verb
Delete verb can be performed only on indexed and relative files. The file must be opened in I-O mode. In sequential file organization, records cannot be deleted. The record last read by the Read statement is deleted in case of sequential access mode. In random access mode, specify the record key and then perform the Delete operation.
Syntax
Following is the syntax to delete a record −
DELETE file-name RECORD INVALID KEY DISPLAY 'Invalid Key' NOT INVALID KEY DISPLAY 'Record Deleted' END-DELETE.Example − to delete an existing record −
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.ENVIRONMENTDIVISION.INPUT-OUTPUTSECTION.FILE-CONTROL.SELECT STUDENT ASSIGNTO OUT101 STUDENT-FILE.05 STUDENT-ID PIC9(4).05 NAME PICA(12).05CLASSPICX(3).WORKING-STORAGESECTION.01 WS-STUDENT.05 WS-STUDENT-ID PIC9(5).05 WS-NAME PICA(25).05 WS-CLASS PICX(3).PROCEDUREDIVISION.OPENI-O STUDENT.MOVE'1000'TO STUDENT-ID.DELETE STUDENT RECORDINVALIDKEYDISPLAY'Invalid Key'NOTINVALIDKEYDISPLAY'Record Deleted'END-DELETE.CLOSE STUDENT.STOPRUN.ORGANIZATIONISINDEXEDACCESSISRANDOMRECORDKEYIS STUDENT-ID FILESTATUSIS FS.DATADIVISION.FILESECTION.FD STUDENTJCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLO //OUT1 DD DSN = OUTPUT-FILE-NAME,DISP = SHRWhen you compile and execute the above program, it produces the following result −
Record DeletedStart Verb
Start verb can be performed only on indexed and relative files. It is used to place the file pointer at a specific record. The access mode must be sequential or dynamic. File must be opened in I-O or Input mode.
Syntax
Following is the syntax to place the pointer at a specific record −
START file-name KEY IS [=, >, <, NOT, <= or >=] rec-key INVALID KEY DISPLAY 'Invalid Key' NOT INVALID KEY DISPLAY 'File Pointer Updated' END-START.Close Verb
Close verb is used to close a file. After performing Close operation, the variables in the file structure will not be available for processing. The link between program and file is lost.
Syntax
Following is the syntax to close a file −
CLOSE file-name.COBOL - Subroutines
Cobol subroutine is a program that can be compiled independently but cannot be executed independently. There are two types of subroutines: internal subroutines like Perform statements and external subroutines like CALL verb.
Call Verb
Call verb is used to transfer the control from one program to another program. The program that contains the CALL verb is the Calling Program and the program being called is known as the Called Program. Calling program execution will halt until the called program finishes the execution. Exit Program statement is used in the Called program to transfer the control back.
Called Program Constraints
Following are the called program requirements −
- Linkage section must be defined in the called program. It consists of data elements passed in the program. The data items should not have Value clause. PIC clause must be compatible with the variables passed through the calling program.
- Procedure division using has a list of variables passed from the calling program and the order must be same as mentioned in the Call verb.
- Exit program statement is used in the called program to transfer the control back. It must be the last statement in the called program.
The parameters can be passed between programs in two ways −
- By Reference
- By Content
Call By Reference
If the values of variables in the called program are modified, then their new values will reflect in the calling program. If BY clause is not specified, then variables are always passed by reference.
Syntax
Following is the syntax of calling subroutine by reference −
CALL sub-prog-name USING variable-1, variable-2.
Example
Following example is the MAIN calling program and UTIL is the called program −
IDENTIFICATIONDIVISION.PROGRAM-ID. MAIN.DATADIVISION.WORKING-STORAGESECTION.01 WS-STUDENT-ID PIC9(4)VALUE1000.01 WS-STUDENT-NAME PICA(15)VALUE'Tim'.PROCEDUREDIVISION.CALL'UTIL'USING WS-STUDENT-ID, WS-STUDENT-NAME.DISPLAY'Student Id : ' WS-STUDENT-ID DISPLAY'Student Name : ' WS-STUDENT-NAME STOPRUN.
Called Program
IDENTIFICATIONDIVISION.PROGRAM-ID. UTIL.DATADIVISION.LINKAGESECTION.01 LS-STUDENT-ID PIC9(4).01 LS-STUDENT-NAME PICA(15).PROCEDUREDIVISIONUSING LS-STUDENT-ID, LS-STUDENT-NAME.DISPLAY'In Called Program'.MOVE1111TO LS-STUDENT-ID.EXITPROGRAM.
JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = MAIN
When you compile and execute the above program, it produces the following result −
In Called Program Student Id : 1111 Student Name : Tim
Call By Content
If the values of variables in the called program are modified, then their new values will not reflect in the calling program.
Syntax
Following is the syntax of calling subroutine by content −
CALL sub-prog-name USING BY CONTENT variable-1, BY CONTENT variable-2.
Example
Following example is the MAIN calling program and UTIL is the called program −
IDENTIFICATIONDIVISION.PROGRAM-ID. MAIN.DATADIVISION.WORKING-STORAGESECTION.01 WS-STUDENT-ID PIC9(4)VALUE1000.01 WS-STUDENT-NAME PICA(15)VALUE'Tim'.PROCEDUREDIVISION.CALL'UTIL'USINGBYCONTENT WS-STUDENT-ID,BYCONTENT WS-STUDENT-NAME.DISPLAY'Student Id : ' WS-STUDENT-ID DISPLAY'Student Name : ' WS-STUDENT-NAME STOPRUN.
Called Program
IDENTIFICATIONDIVISION.PROGRAM-ID. UTIL.DATADIVISION.LINKAGESECTION.01 LS-STUDENT-ID PIC9(4).01 LS-STUDENT-NAME PICA(15).PROCEDUREDIVISIONUSING LS-STUDENT-ID, LS-STUDENT-NAME.DISPLAY'In Called Program'.MOVE1111TO LS-STUDENT-ID.EXITPROGRAM.
JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = MAIN
When you compile and execute the above program, it produces the following result −
In Called Program Student Id : 1000 Student Name : Tim
Types of Call
There are two types of calls −
- Static Call occurs when a program is compiled with the NODYNAM compiler option. A static called program is loaded into storage at compile time.
- Dynamic Call occurs when a program is compiled with the DYNAM and NODLL compiler option. A dynamic called program is loaded into storage at runtime.
COBOL - Internal Sort
Sorting of data in a file or merging of two or more files is a common necessity in almost all business-oriented applications. Sorting is used for arranging records either in ascending or descending order, so that sequential processing can be performed. There are two techniques which are used for sorting files in COBOL −
- External sort is used to sort files by using the SORT utility in JCL. We have discussed this in the JCL chapter. As of now, we will focus on internal sort.
- Internal sort is used to sort files within a COBOL program. SORT verb is used to sort a file.
Sort Verb
Three files are used in the sort process in COBOL −
- Input file is the file which we have to sort either in ascending or descending order.
- Work file is used to hold records while the sort process is in progress. Input file records are transferred to the work file for the sorting process. This file should be defined in the File-Section under SD entry.
- Output file is the file which we get after the sorting process. It is the final output of the Sort verb.
Syntax
Following is the syntax to sort a file −
SORT work-file ON ASCENDING KEY rec-key1 [ON DESCENDING KEY rec-key2] USING input-file GIVING output-file.
SORT performs the following operations −
- Opens work-file in I-O mode, input-file in the INPUT mode and output-file in the OUTPUT mode.
- Transfers the records present in the input-file to the work-file.
- Sorts the SORT-FILE in ascending/descending sequence by rec-key.
- Transfers the sorted records from the work-file to the output-file.
- Closes the input-file and the output-file and deletes the work-file.
Example
In the following example, INPUT is the input file which needs to be sorted in ascending order −
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.ENVIRONMENTDIVISION.INPUT-OUTPUTSECTION.FILE-CONTROL.SELECTINPUTASSIGNTOIN.SELECTOUTPUTASSIGNTO OUT.SELECT WORK ASSIGNTO WRK.DATADIVISION.FILESECTION.FDINPUT.01 INPUT-STUDENT.05 STUDENT-ID-I PIC9(5).05 STUDENT-NAME-I PICA(25).FDOUTPUT.01 OUTPUT-STUDENT.05 STUDENT-ID-O PIC9(5).05 STUDENT-NAME-O PICA(25).SD WORK.01 WORK-STUDENT.05 STUDENT-ID-W PIC9(5).05 STUDENT-NAME-W PICA(25).PROCEDUREDIVISION.SORT WORK ONASCENDINGKEY STUDENT-ID-O USINGINPUTGIVINGOUTPUT.DISPLAY'Sort Successful'.STOPRUN.
JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLO //IN DD DSN = INPUT-FILE-NAME,DISP = SHR //OUT DD DSN = OUTPUT-FILE-NAME,DISP = SHR //WRK DD DSN =&&TEMP
When you compile and execute the above program, it produces the following result −
Sort Successful
Merge Verb
Two or more identically sequenced files are combined using Merge statement. Files used in the merge process −
- Input Files − Input-1, Input-2
- Work File
- Output File
Syntax
Following is the syntax to merge two or more files −
MERGE work-file ONASCENDINGKEY rec-key1 [ONDESCENDINGKEY rec-key2] USING input-1, input-2 GIVING output-file.
Merge performs the following operations −
- Opens the work-file in I-O mode, input-files in the INPUT mode and output-file in the OUTPUT mode.
- Transfers the records present in the input-files to the work-file.
- Sorts the SORT-FILE in ascending/descending sequence by rec-key.
- Transfers the sorted records from the work-file to the output-file.
- Closes the input-file and the output-file and deletes the work-file.
Example
In the following example, INPUT1 and INPUT2 are the input files which are to be merged in ascending order −
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.ENVIRONMENTDIVISION.INPUT-OUTPUTSECTION.FILE-CONTROL.SELECT INPUT1 ASSIGNTO IN1.SELECT INPUT2 ASSIGNTO IN2.SELECTOUTPUTASSIGNTO OUT.SELECT WORK ASSIGNTO WRK.DATADIVISION.FILESECTION.FD INPUT1.01 INPUT1-STUDENT.05 STUDENT-ID-I1 PIC9(5).05 STUDENT-NAME-I1 PICA(25).FD INPUT2.01 INPUT2-STUDENT.05 STUDENT-ID-I2 PIC9(5).05 STUDENT-NAME-I2 PICA(25).FDOUTPUT.01 OUTPUT-STUDENT.05 STUDENT-ID-O PIC9(5).05 STUDENT-NAME-O PICA(25).SD WORK.01 WORK-STUDENT.05 STUDENT-ID-W PIC9(5).05 STUDENT-NAME-W PICA(25).PROCEDUREDIVISION.MERGE WORK ONASCENDINGKEY STUDENT-ID-O USING INPUT1, INPUT2 GIVINGOUTPUT.DISPLAY'Merge Successful'.STOPRUN.
JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP1 EXEC PGM = HELLO //IN1 DD DSN=INPUT1-FILE-NAME,DISP=SHR //IN2 DD DSN=INPUT2-FILE-NAME,DISP=SHR //OUT DD DSN = OUTPUT-FILE-NAME,DISP=SHR //WRK DD DSN =&&TEMP
When you compile and execute the above program, it produces the following result −
Merge Successful
COBOL - Database Interface
As of now, we have learnt the use of files in COBOL. Now, we will discuss how a COBOL program interacts with DB2. It involves the following terms −
- Embedded SQL
- DB2 Application Programming
- Host Variables
- SQLCA
- SQL Queries
- Cursors
Embedded SQL
Embedded SQL statements are used in COBOL programs to perform standard SQL operations. Embedded SQL statements are preprocessed by the SQL processor before the application program is compiled. COBOL is known as the Host Language. COBOL-DB2 applications are those applications that include both COBOL and DB2.
Embedded SQL statements work like normal SQL statements with some minor changes. For example, the output of a query is directed to a predefined set of variables which are referred as Host Variables. An additional INTO clause is placed in the SELECT statement.
DB2 Application Programming
Following are rules to be followed while coding a COBOL-DB2 program −
- All the SQL statements must be delimited between EXEC SQL and ENDEXEC..
- SQL statements must be coded in Area B.
- All the tables that are used in a program must be declared in the WorkingStorage Section. This is done by using the INCLUDE statement.
- All SQL statements other than INCLUDE and DECLARE TABLE must appear in the Procedure Division.
Host Variables
Host variables are used for receiving data from a table or inserting data in a table. Host variables must be declared for all values that are to be passed between the program and the DB2. They are declared in the Working-Storage Section.
Host variables cannot be group items, but they may be grouped together in host structure. They cannot be Renamed or Redefined. Using host variables with SQL statements, prefix them with a colon (:)..
Syntax
Following is the syntax to declare host variables and include tables in the Working-Storage section −
DATADIVISION.WORKING-STORAGESECTION. EXEC SQL INCLUDE table-name END-EXEC. EXEC SQL BEGIN DECLARE SECTION END-EXEC.01 STUDENT-REC.05 STUDENT-ID PIC9(4).05 STUDENT-NAME PICX(25).05 STUDENT-ADDRESS X(50). EXEC SQL END DECLARE SECTION END-EXEC.
SQLCA
SQLCA is a SQL communication area through which DB2 passes the feedback of SQL execution to the program. It tells the program whether an execution was successful or not. There are a number of predefined variables under SQLCA like SQLCODE which contains the error code. The value '000' in SQLCODE states a successful execution.
Syntax
Following is the syntax to declare an SQLCA in the Working-Storage section −
DATA DIVISION. WORKING-STORAGE SECTION. EXEC SQL INCLUDE SQLCA END-EXEC.
SQL Queries
Lets assume we have one table named as 'Student' that contains Student-Id, Student-Name, and Student-Address.
The STUDENT table contains the following data −
Student Id Student Name Student Address 1001 Mohtashim M. Hyderabad 1002 Nishant Malik Delhi 1003 Amitabh Bachan Mumbai 1004 Chulbul Pandey Lucknow
The following example shows the usage of SELECT query in a COBOL program −
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION. EXEC SQLEND-EXEC. EXEC SQLINCLUDE SQLCAEND-EXEC. EXEC SQL BEGIN DECLARE SECTION END-EXEC.01 WS-STUDENT-REC.05 WS-STUDENT-ID PIC9(4).05 WS-STUDENT-NAME PICX(25).05 WS-STUDENT-ADDRESS X(50). EXEC SQL END DECLARE SECTION END-EXEC.PROCEDUREDIVISION. EXEC SQLINCLUDE STUDENTEND-EXEC.IF SQLCODE =0DISPLAY WS-STUDENT-RECORD ELSEDISPLAY'Error'END-IF.STOPRUN.SELECT STUDENT-ID, STUDENT-NAME, STUDENT-ADDRESS INTO:WS-STUDENT-ID,:WS-STUDENT-NAME, WS-STUDENT-ADDRESS FROM STUDENT WHERE STUDENT-ID=1004
JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP001 EXEC PGM = IKJEFT01 //STEPLIB DD DSN = MYDATA.URMI.DBRMLIB,DISP = SHR //SYSPRINT DD SYSOUT=*//SYSUDUMP DD SYSOUT=*//SYSOUT DD SYSOUT=*//SYSTSIN DD * DSN SYSTEM(SSID)RUNPROGRAM(HELLO) PLAN(PLANNAME)-END/*
When you compile and execute the above program, it produces the following result −
1004 Chulbul Pandey Lucknow
The following example shows the usage of INSERT query in a COBOL program −
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION. EXEC SQL INCLUDE SQLCA END-EXEC. EXEC SQL INCLUDE STUDENT END-EXEC. EXEC SQL BEGIN DECLARE SECTION END-EXEC.01 WS-STUDENT-REC.05 WS-STUDENT-ID PIC9(4).05 WS-STUDENT-NAME PICX(25).05 WS-STUDENT-ADDRESS X(50). EXEC SQL END DECLARE SECTION END-EXEC.PROCEDUREDIVISION.MOVE1005TO WS-STUDENT-ID.MOVE'TutorialsPoint'TO WS-STUDENT-NAME.MOVE'Hyderabad'TO WS-STUDENT-ADDRESS. EXEC SQLEND-EXEC.IF SQLCODE =0DISPLAY'Record Inserted Successfully'DISPLAY WS-STUDENT-REC ELSEDISPLAY'Error'END-IF.STOPRUN.INSERT INTO STUDENT(STUDENT-ID, STUDENT-NAME, STUDENT-ADDRESS)VALUES(:WS-STUDENT-ID,:WS-STUDENT-NAME, WS-STUDENT-ADDRESS)
JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP001 EXEC PGM = IKJEFT01 //STEPLIB DD DSN = MYDATA.URMI.DBRMLIB,DISP=SHR //SYSPRINT DD SYSOUT =*//SYSUDUMP DD SYSOUT =*//SYSOUT DD SYSOUT =*//SYSTSIN DD * DSN SYSTEM(SSID)RUNPROGRAM(HELLO) PLAN(PLANNAME)-END/*
When you compile and execute the above program, it produces the following result −
Record Inserted Successfully 1005 TutorialsPoint Hyderabad
The following example shows the usage of UPDATE query in a COBOL program −
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION. EXEC SQL INCLUDE SQLCA END-EXEC. EXEC SQL INCLUDE STUDENT END-EXEC. EXEC SQL BEGIN DECLARE SECTION END-EXEC.01 WS-STUDENT-REC.05 WS-STUDENT-ID PIC9(4).05 WS-STUDENT-NAME PICX(25).05 WS-STUDENT-ADDRESS X(50). EXEC SQL END DECLARE SECTION END-EXEC.PROCEDUREDIVISION.MOVE'Bangalore'TO WS-STUDENT-ADDRESS. EXEC SQLEND-EXEC.IF SQLCODE =0DISPLAY'Record Updated Successfully'ELSEDISPLAY'Error'END-IF.STOPRUN.UPDATE STUDENT SET STUDENT-ADDRESS=:WS-STUDENT-ADDRESS WHERE STUDENT-ID =1003
JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP001 EXEC PGM = IKJEFT01 //STEPLIB DD DSN = MYDATA.URMI.DBRMLIB,DISP = SHR //SYSPRINT DD SYSOUT =*//SYSUDUMP DD SYSOUT =*//SYSOUT DD SYSOUT =*//SYSTSIN DD * DSN SYSTEM(SSID)RUNPROGRAM(HELLO) PLAN(PLANNAME)-END/*
When you compile and execute the above program, it produces the following result −
Record Updated Successfully
The following example shows the usage of DELETE query in a COBOL program −
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION. EXEC SQL INCLUDE SQLCA END-EXEC. EXEC SQL INCLUDE STUDENT END-EXEC. EXEC SQL BEGIN DECLARE SECTION END-EXEC.01 WS-STUDENT-REC.05 WS-STUDENT-ID PIC9(4).05 WS-STUDENT-NAME PICX(25).05 WS-STUDENT-ADDRESS X(50). EXEC SQL END DECLARE SECTION END-EXEC.PROCEDUREDIVISION.MOVE1005TO WS-STUDENT-ID. EXEC SQLEND-EXEC.IF SQLCODE =0DISPLAY'Record Deleted Successfully'ELSEDISPLAY'Error'END-IF.STOPRUN.DELETEFROM STUDENT WHERE STUDENT-ID=:WS-STUDENT-ID
JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP001 EXEC PGM = IKJEFT01 //STEPLIB DD DSN = MYDATA.URMI.DBRMLIB,DISP=SHR //SYSPRINT DD SYSOUT =*//SYSUDUMP DD SYSOUT =*//SYSOUT DD SYSOUT =*//SYSTSIN DD * DSN SYSTEM(SSID)RUNPROGRAM(HELLO) PLAN(PLANNAME)-END/*
When you compile and execute the above program, it produces the following result −
Record Deleted Successfully
Cursors
Cursors are used to handle multiple row selections at a time. They are data structures that hold all the results of a query. They can be defined in the Working-Storage Section or the Procedure Division. Following are the operations associated with Cursor −
- Declare
- Open
- Close
- Fetch
Declare Cursor
Cursor declaration can be done in the Working-Storage Section or the Procedure Division. The first statement is the DECLARE statement which is a nonexecutable statement.
EXEC SQL DECLARE STUDCUR CURSORFORSELECT STUDENT-ID, STUDENT-NAME, STUDENT-ADDRESS FROM STUDENT WHERE STUDENT-ID >:WS-STUDENT-ID END-EXEC.
Open
Before using a cursor, Open statement must be performed. The Open statement prepares the SELECT for execution.
EXEC SQL OPEN STUDCUR END-EXEC.
Close
Close statement releases all the memory occupied by the cursor. It is mandatory to close a cursor before ending a program.
EXEC SQL CLOSE STUDCUR END-EXEC.
Fetch
Fetch statement identifies the cursor and puts the value in the INTO clause. A Fetch statement is coded in loop as we get one row at a time.
EXEC SQL FETCH STUDCUR INTO:WS-STUDENT-ID,:WS-STUDENT-NAME, WS-STUDENT-ADDRESS END-EXEC.
The following example shows the usage of cursor to fetch all the records from the STUDENT table −
IDENTIFICATIONDIVISION.PROGRAM-ID. HELLO.DATADIVISION.WORKING-STORAGESECTION. EXEC SQL INCLUDE SQLCA END-EXEC. EXEC SQL INCLUDE STUDENT END-EXEC. EXEC SQL BEGIN DECLARE SECTION END-EXEC.01 WS-STUDENT-REC.05 WS-STUDENT-ID PIC9(4).05 WS-STUDENT-NAME PICX(25).05 WS-STUDENT-ADDRESS X(50). EXEC SQL END DECLARE SECTION END-EXEC. EXEC SQLEND-EXEC.PROCEDUREDIVISION.MOVE1001TO WS-STUDENT-ID.PERFORMUNTIL SQLCODE =100 EXEC SQLDECLARE STUDCUR CURSORFORSELECT STUDENT-ID, STUDENT-NAME, STUDENT-ADDRESS FROM STUDENT WHERE STUDENT-ID >:WS-STUDENT-IDEND-EXEC DISPLAY WS-STUDENT-REC END-PERFORMSTOPRUN.FETCH STUDCUR INTO:WS-STUDENT-ID,:WS-STUDENT-NAME, WS-STUDENT-ADDRESS
JCL to execute the above COBOL program −
//SAMPLE JOB(TESTJCL,XXXXXX),CLASS= A,MSGCLASS = C //STEP001 EXEC PGM=IKJEFT01 //STEPLIB DD DSN=MYDATA.URMI.DBRMLIB,DISP=SHR //SYSPRINT DD SYSOUT=*//SYSUDUMP DD SYSOUT=*//SYSOUT DD SYSOUT=*//SYSTSIN DD * DSN SYSTEM(SSID)RUNPROGRAM(HELLO) PLAN(PLANNAME)-END/*
When you compile and execute the above program, it produces the following result −
1001 Mohtashim M. Hyderabad 1002 Nishant Malik Delhi 1003 Amitabh Bachan Mumbai 1004 Chulbul Pandey Lucknow
