DB2 SQL Web Pagination - How to tell I reach EOF - sql

Question

Friends,
I am trying to find a very simple solution to tell me I have reach the End of file with a Web Pagination, using Fetch Next. I am using Previous & Next button to trigger stored procedure.
**FREE
// RFC Main Grid
CTL-OPT NOMAIN OPTION (*SRCSTMT : *NODEBUGIO);
DCL-PROC PUR027 EXPORT;
DCL-PI PUR027 EXTPROC(*DCLCASE);
StartingRow PACKED(3:0);
NbrOfRows PACKED(3:0);
TotalRows CHAR(10);
RowCount CHAR(10);
Search CHAR(30);
EndOfFile CHAR(3);
BOF CHAR(1);
EOF CHAR(1);
RSL CHAR(2);
END-PI;
IF Search = '';
EXEC SQL
Declare RSCURSOR cursor for
SELECT CDEPT, CDESC, ROW_NUMBER() OVER(ORDER BY CDESC, CDEPT) as ROWNUMBER
FROM CDPL03
ORDER BY CDESC, CDEPT
OFFSET (:StartingRow - 1) * :NbrOfRows ROWS
FETCH NEXT :NbrOfRows ROWS ONLY;
EXEC SQL Open RSCURSOR;
EXEC SQL SET RESULT SETS Cursor RSCURSOR;
ELSE;
EXEC SQL
Declare RSCURSOR2 cursor for
SELECT CDEPT, CDESC, ROW_NUMBER() OVER(ORDER BY CDESC, CDEPT) as ROWNUMBER
FROM CDPL03
WHERE CDESC LIKE '%' concat trim(:Search) concat '%' OR
CDEPT LIKE '%' concat trim(:Search) concat '%'
ORDER BY CDESC, CDEPT
OFFSET (:StartingRow - 1) * :NbrOfRows ROWS
FETCH NEXT :NbrOfRows ROWS ONLY;
EXEC SQL Open RSCURSOR2;
EXEC SQL SET RESULT SETS Cursor RSCURSOR2;
ENDIF;
// Begin & End of File
IF StartingRow = 1;
BOF = '1';
EOF = '0';
ELSE;
BOF = '0';
EOF = '0';
ENDIF;
// Validate for SQL errors
IF SQLSTATE = '00000';
RSL = '00';
//TotalRows2 = %CHAR(TotalRows);
ELSEIF SQLSTATE = '02000';
RSL = '10';
ELSE;
RSL = '20';
ENDIF;
RETURN;
END-PROC PUR027;
// To create the service program:
// CRTSRVPGM SRVPGM(BPCSO/PUR027WS)
// MODULE(BPCSO/PUR027W)
// SRCFILE(BPCSS/PURBNDF) SRCMBR(PUR027WB)

Answer 1

When reading multiple records in a block, I retrieve the number of records fetched with GET DIAGNOSTICS like this:
exec sql get diagnostics
:cnt = row_count;
Then if the number of records fetched is less than the requested number of records, I know that I am on the last page.
There is a problem with this method though. If the last page is full, you don't know it until you try to read the next page, and it is empty. So one way to handle that is to request one record more than you are going to present on the page. That is, if you are presenting 25 records per page, request 26. If your result set has 26 records, then there is at least one record on the next page. Still only present 25 records, and increment your offset by 25 records each time, just request 26 records. If the record set has less than 26 records, then you know you are on the last page.

Answer 2

Take a look at SQLERRD(2)
For an OPEN statement, if the cursor is insensitive to changes, SQLERRD(2) contains the actual number of rows in the result set. If the cursor is sensitive to changes, SQLERRD(2) contains an estimated number of rows in the result set.
You can also use GET DIAGNOSTICS after the open for the same info...
DB2_NUMBER_ROWS
If the previous SQL statement was an OPEN or a FETCH which caused the size of the result table to be known, returns the number of rows in the result table. For SENSITIVE cursors, this value can be thought of as an approximation since rows inserted and deleted will affect the next retrieval of this value. Otherwise, the value zero is returned.
Key point for both, for an exact count, you'd need to declare your cursor INSENSITIVE which will create a copy of your selected rows so that inserts, deletes and updates don't affect the results. There's also a performance hit.