Re: embedded sql and alwcpydta

[CRPence <CRPbottle@xxxxxxxxx>]

  AFaIK the precompiler will maintain an update capable cursor as 
"updatable" [see that fake word and "deletable" for delete capable 
references in the DECLARE CURSOR documentation], knowing that it is 
referred to by an UPDATE WHERE CURRENT OF statement.  Even if there 
is a concern for any particular cursor, just specify the FOR UPDATE 
[OF] clause.  Unlike preventing temporary data generally, using that 
FOR UPDATE OF clause avoids the possibility that other non-update 
[AKA read-only] cursors will be prevented from optimal I\O 
characteristics due to the Allow Copy Data feature being denied. 
Similarly the FOR READ ONLY clause prevents an otherwise update 
capable cursor from remaining "updatable" even if not referenced in 
a WHERE CURRENT OF; the DECLARE CURSOR documentation even notes that 
if "a cursor is not going to be used in a Positioned UPDATE or 
DELETE statement," then "it should be declared as FOR READ ONLY." 
So probably just leave the ALWCPYDTA(*YES | *OPTIMIZE), and 
explicitly tell the SQL pre-compiler of any plans to update via any 
particular cursor; and that FOR UPDATE OF is actually required when 
the cursor has an ORDER BY, for which the query implementation by 
temporary data copy is most probable.

http://publib.boulder.ibm.com/infocenter/iseries/v6r1m0/topic/db2/rbafzh2dclcu.htm
http://publib.boulder.ibm.com/infocenter/iseries/v6r1m0/topic/sqlp/rbafycurs5a.htm

Regards, Chuck

JDHorn@xxxxxxxxxxxxxx wrote:
> when embedding sql in rpg, when selecting via a cursor and doing
> an update/delete using "current of cursor", will the compiler
> "know" you don't want to create a temporary copy of the data or
> might it do it anyway?
>
> if the above is that it might copy the data, is there a compiler
> directive for alwcpydta(*no)?