Re: Using DataStructure in Update Query in RPG ?

[vhamberg@xxxxxxxxxxx]

Dave, I think you are using the term "data structure" differently than the 
poster meant. It is a specific term of art in RPG, similar to a struct in C. 
Your SAL-REC in COBOL is the closest thing to it, but the example there is a 
SELECT INTO, not an UPDATE. The idea is to use what the SQL books call a "host 
structure" instead of a comma-delimited list of "host variables". It is a 
shortcut which the UPDATE did not used to have. At V5R1 it became possible to 
use the syntax Birgitta mentioned, "set row = :dsname" which assumes that the 
DS (RPG data structure) has elements for all the columns in the row.

Murky? Sorry if it is.

Later
Vern

-------------- Original message -------------- 
From: "Dave Odom" <Dave.Odom@xxxxxxxxxxxx> 

> Luqman, 
> 
> Let me give you a few examples in different languages and see if this 
> helps. If not, please explain further. The following are examples of 
> the UPDATE statement using data structures in programs in C, COBOL and 
> REXX: 
> 
> void main () 
> { 
> EXEC SQL BEGIN DECLARE SECTION; 
> decimal(5,2) AMOUNT; 
> char FROM_EMPNO[7]; 
> char TO_EMPNO[7]; 
> EXEC SQL END DECLARE SECTION; 
> EXEC SQL INCLUDE SQLCA; 
> EXEC SQL WHENEVER SQLERROR GOTO SQLERR; 
> ... 
> EXEC SQL UPDATE EMPLOYEE 
> SET COMM = COMM - :AMOUNT 
> WHERE EMPNO = :FROM_EMPNO; 
> EXEC SQL UPDATE EMPLOYEE 
> SET COMM = COMM + :AMOUNT 
> WHERE EMPNO = :TO_EMPNO; 
> FINISHED: 
> EXEC SQL COMMIT WORK; 
> return; 
> 
> For example, in COBOL: 
> 01 SAL-REC. 
> 10 MIN-SAL PIC S9(6)V99 USAGE COMP-3. 
> 10 AVG-SAL PIC S9(6)V99 USAGE COMP-3. 
> 10 MAX-SAL PIC S9(6)V99 USAGE COMP-3. 
> 01 SALTABLE. 
> 02 SALIND PIC S9999 USAGE COMP-4 OCCURS 3 TIMES. 
> 01 EDUC-LEVEL PIC S9999 COMP-4. 
> ... 
> MOVE 20 TO EDUC-LEVEL. 
> ... 
> EXEC SQL 
> SELECT MIN(SALARY), AVG(SALARY), MAX(SALARY) 
> INTO :SAL-REC:SALIND 
> FROM CORPDATA.EMPLOYEE 
> WHERE EDLEVEL>:EDUC-LEVEL 
> END-EXEC. 
> 
> REXX: 
> 
> ADDRESS '*COMMAND', 
> SIGNAL ON ERROR 
> UPDATE_STMT = 'UPDATE CORPDATA/EMPLOYEE ', 
> 'SET SALARY = SALARY * ? ', 
> 'WHERE COMM >= ? ' 
> EXECSQL, 
> 'PREPARE S1 FROM :UPDATE_STMT' 
> EXECSQL, 
> 'EXECUTE S1 USING :PERCENTAGE,', 
> ' :COMMISSION ' 
> /* Commit changes */ 
> EXECSQL, 
> 'COMMIT' 
> 
> HTH, 
> 
> Dave 
> -- 
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