Author:
NikhilGuptaGaya
Subject: Need help - DB2 Dynamic SQL Program embeded in Cobol
Posted: Sat Jun 23, 2018 1:58 pm (GMT 5.5)
Hi All,
I will need your help in clearing my doubts that haunted me for each time I start studying DB2.
Got following queries -
1. Regarding Prepare statement, let's take below example -
MOVE "DELETE FROM SAMPLETABLE WHERE DEPTNO = 'A00'"
TO STRING-VARIABLE.
EXEC SQL
PREPARE STMT1 FROM :STRING-VARIABLE;
END-EXEC.
EXEC SQL
EXECUTE STMT1;
END-EXEC.
I didn't get where "STMT1" is declared/defined in Working Storage of cobol program. Does it require to be defined in the working storage or not? if yes then how and what should be it's picture clause and length.
2) It's regarding Dynamic SQL....
Move "SQL query" to WorkingStorge-HostVariable.
Above "SQL Query" can be given at runtime using SYSIN DD control statement of JCL?
3) If "YES" that sql query can be given to the program using SYSIN DD DATA statement of JCL then how SQLDA becomes useful?
also can you give me one complete example of it having step by step without any confusion or missing declaring/definition in the working storage?
4) It's regarding varying list select query....let's take below example -
SQL to execute: SELECT PROJNO, PROJNAME, RESPEMP
FROM DSN8810.PROJ
WHERE PROJNO = 'A00'
AND PRSTDATE = '1988-10-10';
Move the "SQL to execute" to STRING-VARIABLE
EXEC SQL DECLARE CSR3 CURSOR FOR VLSQL;
EXEC SQL
PREPARE VLSQL INTO SQLDA FROM :STRING-VARIABLE;
EXEC SQL OPEN CSR3;
Load storage addresses into the SQLDA
Loop until no more rows to FETCH
EXEC SQL FETCH CSR3 USING DESCRIPTOR SQLDA;
EXEC SQL CLOSE CSR3;
In above query, I'm not getting followings -
a. where VLSQL is defined in program? what's its picture clause and length?
b. How SQLDA is used to define & mapped column of select query?
c. fetch cursor using decriptor SQLDA.....how columns are mapped to host variable? is it not required to be declared in the working storage section?
also could you explain below code snippet - it's not clear to me....
EXEC SQL INCLUDE SQLDA
EXEC SQL INCLUDE MINSQLDA
Read "SQL to execute" from external source
Move the "SQL to execute" to STRING-VARIABLE
EXEC SQL DECLARE CSR3 CURSOR FOR VLSQL;
EXEC SQL
PREPARE VLSQL INTO MINSQLDA FROM :STRING-VARIABLE;
IF SQLD IN MINSQLDA = 0
EXECUTE IMMEDIATE (SQL statement was not a SELECT)
FINISHED.
EXEC SQL
PREPARE VLSQL INTO SQLDA FROM :STRING-VARIABLE;
EXEC SQL OPEN CSR3;
Load storage addresses into the SQLDA
Loop until no more rows to FETCH
EXEC SQL FETCH CSR3 USING DESCRIPTOR SQLDA;
EXEC SQL CLOSE CSR3;
Please suggest...
Thank you....
_________________
Regards,
Nikhil Gupta
