invalid level number 'EXEC' error in OpenCOBOL - cobol

Question

this is my code Here :
******************************************************************
* Open Cobol ESQL (Ocesql) Sample Program
*
* FETCHTBL --- demonstrates CONNECT, SELECT COUNT(*),
* DECLARE cursor, FETCH cursor, COMMIT,
* ROLLBACK, DISCONNECT
*
* Copyright 2013 Tokyo System House Co., Ltd.
******************************************************************
IDENTIFICATION DIVISION.
******************************************************************
PROGRAM-ID. FETCHTBL.
******************************************************************
DATA DIVISION.
******************************************************************
WORKING-STORAGE SECTION.
01 D-EMP-REC.
05 D-EMP-NO PIC 9(04).
05 FILLER PIC X.
05 D-EMP-NAME PIC X(20).
05 FILLER PIC X.
05 D-EMP-SALARY PIC --,--9.
EXEC SQL BEGIN DECLARE SECTION END-EXEC.
01 DBNAME PIC X(30) VALUE SPACE.
01 USERNAME PIC X(30) VALUE SPACE.
01 PASSWD PIC X(10) VALUE SPACE.
01 EMP-REC-VARS.
05 EMP-NO PIC S9(04).
05 EMP-NAME PIC X(20) .
05 EMP-SALARY PIC S9(04).
01 EMP-CNT PIC 9(04).
EXEC SQL END DECLARE SECTION END-EXEC.
EXEC SQL INCLUDE SQLCA END-EXEC.
******************************************************************
PROCEDURE DIVISION.
******************************************************************
MAIN-RTN.
DISPLAY "*** FETCHTBL STARTED ***".
* WHENEVER IS NOT YET SUPPORTED :(
* EXEC SQL WHENEVER SQLERROR PERFORM ERROR-RTN END-EXEC.
* CONNECT
MOVE "testdb" TO DBNAME.
MOVE "postgres" TO USERNAME.
MOVE SPACE TO PASSWD.
EXEC SQL
CONNECT :USERNAME IDENTIFIED BY :PASSWD USING :DBNAME
END-EXEC.
IF SQLCODE NOT = ZERO PERFORM ERROR-RTN STOP RUN.
* SELECT COUNT(*) INTO HOST-VARIABLE
EXEC SQL
SELECT COUNT(*) INTO :EMP-CNT FROM EMP
END-EXEC.
DISPLAY "TOTAL RECORD: " EMP-CNT.
* DECLARE CURSOR
EXEC SQL
DECLARE C1 CURSOR FOR
SELECT EMP_NO, EMP_NAME, EMP_SALARY
FROM EMP
ORDER BY EMP_NO
END-EXEC.
EXEC SQL
OPEN C1
END-EXEC.
* FETCH
DISPLAY "---- -------------------- ------".
DISPLAY "NO NAME SALARY".
DISPLAY "---- -------------------- ------".
EXEC SQL
FETCH C1 INTO :EMP-NO, :EMP-NAME, :EMP-SALARY
END-EXEC.
PERFORM UNTIL SQLCODE NOT = ZERO
MOVE EMP-NO TO D-EMP-NO
MOVE EMP-NAME TO D-EMP-NAME
MOVE EMP-SALARY TO D-EMP-SALARY
DISPLAY D-EMP-REC
EXEC SQL
FETCH C1 INTO :EMP-NO, :EMP-NAME, :EMP-SALARY
END-EXEC
END-PERFORM.
* CLOSE CURSOR
EXEC SQL
CLOSE C1
END-EXEC.
* COMMIT
EXEC SQL
COMMIT WORK
END-EXEC.
* DISCONNECT
EXEC SQL
DISCONNECT ALL
END-EXEC.
* END
DISPLAY "*** FETCHTBL FINISHED ***".
STOP RUN.
******************************************************************
ERROR-RTN.
******************************************************************
DISPLAY "*** SQL ERROR ***".
DISPLAY "SQLCODE: " SQLCODE " " NO ADVANCING.
EVALUATE SQLCODE
WHEN +10
DISPLAY "Record not found"
WHEN -01
DISPLAY "Connection falied"
WHEN -20
DISPLAY "Internal error"
WHEN -30
DISPLAY "PostgreSQL error"
DISPLAY "ERRCODE: " SQLSTATE
DISPLAY SQLERRMC
*> TO RESTART TRANSACTION, DO ROLLBACK.
EXEC SQL
ROLLBACK
END-EXEC
WHEN OTHER
DISPLAY "Undefined error"
DISPLAY "ERRCODE: " SQLSTATE
DISPLAY SQLERRMC
END-EVALUATE.
******************************************************************

Answer 1

This is not "pure COBOL", but COBOL with embedded SQL, which in most cases needs a precompiler.
As-is there is a word EXEC where in COBOL a level-number would be expected, therefore the message from your compiler is correct.
In order to compile this source with your COBOL compiler, use an EXEC SQL precompiler to convert the SQL statements into COBOL for you first, most likely the one that the sample program references: ocesql - Open-COBOL-ESQL (PostgreSQL only).
As an alterative you can also use other preparsers (likely with some adjustments, especially for the CONNECT); here's an incomplete list:
esqlOC - ESQL for GnuCOBOL/OpenCobol (also works with other compilers, uses ODBC under the hood)
Gix ESQL, a recent addition, currently only as part of the Gix-IDE (GnuCOBOL only, currently uses a general ODBC or direct binding to PostgreSQL or MySql)
... and some proprietary variants (only to access their products)
Oracle Pro*COBOL
IBM DB2 precompiler
...