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An important use for BEFORE BREAK
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BEFORE BREAK PROCESSING can be an important clause in structuring a Natural program.
The three programs in this post show the need for this clause when using IF...ESCAPE TOP
(or ACCEPT/REJECT) inconjunction with AT BREAK.
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* THIS IS THE FIRST IN A SERIES OF THREE PROGRAMS
* THAT SHOW AN IMPORTANT USE FOR BEFORE BREAK PROCESSING.
* THIS FIRST PROGRAM IS NOT PARTICULARLY EXCITING.
* WE ARE MERELY READING A SERIES OF RECORDS FROM
* OUR FILE IN LOGICAL SEQUENCE BY NAME.
*
* AT THE BREAK OF THE NAME FIELD WE SIMPLY WRITE OUT THE
* NAME THAT WAS JUST COMPLETED AND THE NAME THAT WILL
* BE PROCESSED NEXT.
*
* THE "IF NAME NE OLD (NAME)" STATEMENT ELIMINATES A
* DOUBLE PRINTING OF THE LAST NAME.
* (COMMENT OUT THE "IF" AND THE "END-IF" AND RUN
* TO SEE WHAT I MEAN).
*
DEFINE DATA LOCAL
1 MYVIEW VIEW OF EMPLOYEES
2 NAME
2 FIRST-NAME
2 SALARY (1)
END-DEFINE
*
INCLUDE AATITLER
INCLUDE AASETC
*
READ (15) MYVIEW IN LOGICAL SEQUENCE
BY NAME STARTING FROM 'JONES'
*
AT BREAK OF NAME
WRITE // 10T 'END OF NAME' OLD (NAME)
IF NAME NE OLD (NAME)
WRITE // 10T 'NEXT NAME IS' NAME
END-IF
NEWPAGE
END-BREAK
*
DISPLAY 5T NAME FIRST-NAME SALARY (1)
END-READ
*
END
-------------------------------------------------------
Output from the program above:
PAGE # 1 DATE: 03/16/11
PROGRAM: BEFORE05 LIBRARY: SNIPPET
NAME FIRST-NAME ANNUAL
SALARY
-------------------- -------------------- ----------
JONES VIRGINIA 46000
JONES MARSHA 50000
JONES ROBERT 31000
JONES LILLY 24000
JONES EDWARD 37600
JONES MARTHA 21000
JONES LAUREL 30000
JONES KEVIN 7000
JONES GREGORY 4800
END OF NAME JONES
NEXT NAME IS JOPER
-----------------------------------------------------------
PAGE # 2 DATE: 03/16/11
PROGRAM: BEFORE05 LIBRARY: SNIPPET
NAME FIRST-NAME ANNUAL
SALARY
-------------------- -------------------- ----------
JOPER MANFRED 24923
END OF NAME JOPER
NEXT NAME IS JOUSSELIN
----------------------------------------------------------
PAGE # 3 DATE: 03/16/11
PROGRAM: BEFORE05 LIBRARY: SNIPPET
NAME FIRST-NAME ANNUAL
SALARY
-------------------- -------------------- ----------
JOUSSELIN DANIEL 1036
END OF NAME JOUSSELIN
NEXT NAME IS JUBE
---------------------------------------------------------
PAGE # 4 DATE: 03/16/11
PROGRAM: BEFORE05 LIBRARY: SNIPPET
NAME FIRST-NAME ANNUAL
SALARY
-------------------- -------------------- ----------
JUBE GABRIEL 783
END OF NAME JUBE
NEXT NAME IS JUNG
--------------------------------------------------------
PAGE # 5 DATE: 03/16/11
PROGRAM: BEFORE05 LIBRARY: SNIPPET
NAME FIRST-NAME ANNUAL
SALARY
-------------------- -------------------- ----------
JUNG ERNST 24358
END OF NAME JUNG
NEXT NAME IS JUNKIN
----------------------------------------------------------
PAGE # 6 DATE: 03/16/11
PROGRAM: BEFORE05 LIBRARY: SNIPPET
NAME FIRST-NAME ANNUAL
SALARY
-------------------- -------------------- ----------
JUNKIN JEREMY 6800
END OF NAME JUNKIN
NEXT NAME IS KAISER
-----------------------------------------------------------
PAGE # 7 DATE: 03/16/11
PROGRAM: BEFORE05 LIBRARY: SNIPPET
NAME FIRST-NAME ANNUAL
SALARY
-------------------- -------------------- ----------
KAISER REINER 24358
END OF NAME KAISER
-----------------------------------------------------------
Now we complicate matters by adding an IF...ESCAPE TOP clause
to exclude certain records from being processed. We could also
have used ACCEPT/REJECT. The "messed up" output is the same
in both cases.
* NOW FOR WHAT SHOULD BE A SIMPLE CHANGE. WE ONLY
* WISH TO DISPLAY RECORDS IF THE SALARY IS GREATER THAN
* OR EQUAL TO 24,000.
*
* IN THIS PROGRAM WE ERRONEOUSLY ADDED JUST
* A SIMPLE IF...ESCAPE TOP TO OUR PREVIOUS PROGRAM.
*
* IF YOU TAKE A LOOK AT THE OUTPUT BELOW YOU WILL
* SEE WHAT A MESS WE CREATED.
*
* IN PARTICULAR, LOOK AT THE PAGES WITH JOPER-JOSSELIN
* OR JOPER-JUBE ETC. NO OUTPUT ON THESE PAGES.
* ASLO, THERE ARE NAMES THAT APPEAR AS "NEXT NAME"
* WHICH NEVER APPEAR.
*
* THE PROBLEM IS QUITE SIMPLE. THE AT BREAK TEST IS
* DONE BEFORE THE IF...ESCAPE TOP TEST. ALSO, ALL
* THE RECORDS FOR A GIVEN NAME MAY FAIL OUR SALARY TEST.
*
DEFINE DATA LOCAL
1 MYVIEW VIEW OF EMPLOYEES
2 NAME
2 FIRST-NAME
2 SALARY (1)
END-DEFINE
*
INCLUDE AATITLER
INCLUDE AASETC
*
READ (15) MYVIEW IN LOGICAL SEQUENCE
BY NAME STARTING FROM 'JONES'
*
IF SALARY (1) LT 24000
ESCAPE TOP
END-IF
*
AT BREAK OF NAME
WRITE // 10T 'END OF NAME' OLD (NAME)
IF NAME NE OLD (NAME)
WRITE // 10T 'NEXT NAME IS' NAME
END-IF
NEWPAGE
END-BREAK
*
DISPLAY 5T NAME FIRST-NAME SALARY (1)
END-READ
*
END
-------------------------------------------------------
Output from the program above
PAGE # 1 DATE: 03/16/11
PROGRAM: BEFORE06 LIBRARY: SNIPPET
NAME FIRST-NAME ANNUAL
SALARY
-------------------- -------------------- ----------
JONES VIRGINIA 46000
JONES MARSHA 50000
JONES ROBERT 31000
JONES LILLY 24000
JONES EDWARD 37600
JONES LAUREL 30000
END OF NAME JONES
NEXT NAME IS JOPER
---------------------------------------------------------
PAGE # 2 DATE: 03/16/11
PROGRAM: BEFORE06 LIBRARY: SNIPPET
NAME FIRST-NAME ANNUAL
SALARY
-------------------- -------------------- ----------
JOPER MANFRED 24923
END OF NAME JOPER
NEXT NAME IS JOUSSELIN
---------------------------------------------------------
PAGE # 3 DATE: 03/16/11
PROGRAM: BEFORE06 LIBRARY: SNIPPET
NAME FIRST-NAME ANNUAL
SALARY
-------------------- -------------------- ----------
END OF NAME JOPER
NEXT NAME IS JUBE
----------------------------------------------------------
PAGE # 4 DATE: 03/16/11
PROGRAM: BEFORE06 LIBRARY: SNIPPET
NAME FIRST-NAME ANNUAL
SALARY
-------------------- -------------------- ----------
END OF NAME JOPER
NEXT NAME IS JUNG
--------------------------------------------------------
PAGE # 5 DATE: 03/16/11
PROGRAM: BEFORE06 LIBRARY: SNIPPET
NAME FIRST-NAME ANNUAL
SALARY
-------------------- -------------------- ----------
JUNG ERNST 24358
END OF NAME JUNG
NEXT NAME IS JUNKIN
----------------------------------------------------------
PAGE # 6 DATE: 03/16/11
PROGRAM: BEFORE06 LIBRARY: SNIPPET
NAME FIRST-NAME ANNUAL
SALARY
-------------------- -------------------- ----------
END OF NAME JUNG
NEXT NAME IS KAISER
--------------------------------------------------------
PAGE # 7 DATE: 03/16/11
PROGRAM: BEFORE06 LIBRARY: SNIPPET
NAME FIRST-NAME ANNUAL
SALARY
-------------------- -------------------- ----------
KAISER REINER 24358
END OF NAME KAISER
---------------------------------------------------------
Now we will use BEFORE BREAK to correct our program:
* HERE IS A SOLUTION TO THE PROBLEM SHOWN ABOVE IN BEFORE06.
*
* THE IF...ESCAPE TOP CLAUSE IS NOW WITHIN A
* BEFORE BREAK CLAUSE, WHICH IS EXECUTED BEFORE
* THE AT BREAK CLAUSE.
*
DEFINE DATA LOCAL
1 MYVIEW VIEW OF EMPLOYEES
2 NAME
2 FIRST-NAME
2 SALARY (1)
END-DEFINE
*
INCLUDE AATITLER
INCLUDE AASETC
*
READ (15) MYVIEW IN LOGICAL SEQUENCE
BY NAME STARTING FROM 'JONES'
*
BEFORE BREAK PROCESSING
IF SALARY (1) LT 24000
ESCAPE TOP
END-IF
END-BEFORE
*
AT BREAK OF NAME
WRITE // 10T 'END OF NAME' OLD (NAME)
IF NAME NE OLD (NAME)
WRITE // 10T 'NEXT NAME IS' NAME
END-IF
NEWPAGE
END-BREAK
*
DISPLAY 5T NAME FIRST-NAME SALARY (1)
END-READ
*
END
---------------------------------------------------
Output from the program above:
PAGE # 1 DATE: 03/16/11
PROGRAM: BEFORE07 LIBRARY: SNIPPET
NAME FIRST-NAME ANNUAL
SALARY
-------------------- -------------------- ----------
JONES VIRGINIA 46000
JONES MARSHA 50000
JONES ROBERT 31000
JONES LILLY 24000
JONES EDWARD 37600
JONES LAUREL 30000
END OF NAME JONES
NEXT NAME IS JOPER
---------------------------------------------------------
PAGE # 2 DATE: 03/16/11
PROGRAM: BEFORE07 LIBRARY: SNIPPET
NAME FIRST-NAME ANNUAL
SALARY
-------------------- -------------------- ----------
JOPER MANFRED 24923
END OF NAME JOPER
NEXT NAME IS JUNG
----------------------------------------------------------
PAGE # 3 DATE: 03/16/11
PROGRAM: BEFORE07 LIBRARY: SNIPPET
NAME FIRST-NAME ANNUAL
SALARY
-------------------- -------------------- ----------
JUNG ERNST 24358
END OF NAME JUNG
NEXT NAME IS KAISER
--------------------------------------------------------
PAGE # 4 DATE: 03/16/11
PROGRAM: BEFORE07 LIBRARY: SNIPPET
NAME FIRST-NAME ANNUAL
SALARY
-------------------- -------------------- ----------
KAISER REINER 24358
END OF NAME KAISER
---------------------------------------------------------
Note in the output from BEFORE07, there are no pages without records.
Compare the four pages from BEFORE07 with the seven pages from BEFORE06.
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Description :
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Disclaimer :
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Utilities and samples shown here are not official parts of the Software AG products. These utilities and
samples are not eligible for technical support through Software AG Customer Care.
Software AG makes no guarantees pertaining to the functionality, scalability, robustness, or degree of
testing of these utilities and samples. Customers are strongly advised to consider these utilities and samples as "working examples" from which
they should build and test their own solutions
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