Обсуждение: ECPG - cursor fetch
I'm doing a port from Sybase's pre-compiler cpre, to ecpg and I have a couple of questions (if anyone has the time). This relates to cursors and fetching, and what I would like to do is retrieve a bunch of records at one time - cpre is able to fetch values into an array...
EXEC SQL BEGIN DECLARE SECTION;
int myInts[100];
EXEC SQL END DECLARE SECTION;
...
EXEC SQL DECLARE myCursor FOR SELECT
myInt FROM myTable;
EXEC SQL FETCH myCursor INTO
:myInts;
There is one mechanism that cpre uses to make sure that you don't exceed the array size...
EXEC SQL OPEN myCursor ROW_COUNT=100;
then, every time you do a fetch, it retrives 100 rows.
I'm not asking for this exact thing in ecpg, but what mechanisms are available for a similar type of response, rather than looping the fetch statement a bunch of times?
Also, since I'm in the middle of a port, I'm trying to make the code work for both with a different compile flag - but the pre-compilers don't care about #defines. Is there some other mecanism to tell ecpg to ignore or skip a section? I really don't want to have to make a "Pre-pre-compiler".
I thought I would share this - the ecpg pre-compiler is much easier to work with, and it handles things better than cpre when it comes to code generation. I think it would be much easier to port from ecpg to cpre than what I am doing, because a lot of the non-standard options that are available used/forced in cpre. So thanks for all the work you guys have done.
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On Thu, Mar 10, 2005 at 01:51:07PM -0800, Mark Richardson wrote: > I'm doing a port from Sybase's pre-compiler cpre, to ecpg and I have a couple of questions (if anyone has the time). Thisrelates to cursors and fetching, and what I would like to do is retrieve a bunch of records at one time - cpre is ableto fetch values into an array... > EXEC SQL BEGIN DECLARE SECTION; > int myInts[100]; > EXEC SQL END DECLARE SECTION; > ... > EXEC SQL DECLARE myCursor FOR SELECT > myInt FROM myTable; > > EXEC SQL FETCH myCursor INTO > :myInts; > > There is one mechanism that cpre uses to make sure that you don't exceed the array size... > EXEC SQL OPEN myCursor ROW_COUNT=100; > then, every time you do a fetch, it retrives 100 rows. This is usually done in the fetch statement and not in the open one. Just use EXEC SQL FETCH 100 myCursor INTO :myInts; > Also, since I'm in the middle of a port, I'm trying to make the code work for both with a different compile flag - butthe pre-compilers don't care about #defines. Is there some other mecanism to tell ecpg to ignore or skip a section? I really don't want to have to make a "Pre-pre-compiler". EXEC SQL DEFINE/IFDEF/... > I thought I would share this - the ecpg pre-compiler is much easier to work with, and it handles things better than cprewhen it comes to code generation. I think it would be much easier to port from ecpg to cpre than what I am doing, becausea lot of the non-standard options that are available used/forced in cpre. So thanks for all the work you guys havedone. Nice to hear that. :-) Michael -- Michael Meskes Email: Michael at Fam-Meskes dot De ICQ: 179140304, AIM/Yahoo: michaelmeskes, Jabber: meskes@jabber.org Go SF 49ers! Go Rhein Fire! Use Debian GNU/Linux! Use PostgreSQL!