Re: Scroll cursor vs ROWID array
True, but, using the SCROLL CURSOR, you won't need to worry about running out of memory. Perry Dillard writes: * * }>>>>>>>>> Perry's response to Kerry Sainsbury <<<<<<<<<< * Or you'd at least have to dynamically allocate memory through * calls to c functions if we are talking 4GL. Otherwise, if you * are using esql/c you have no problem with allocating memory. * * } From: kerry@kcbbs.gen.nz (Kerry Sainsbury) * } Subject: RE: Scroll cursor vs ROWID array * } Date: Fri, 05 Apr 1996 07:17:53 +1200 * } To: informix-list@rmy.emory.edu * } * } In article <4jp78d$dvk@cssun.mathcs.emory.edu>, * } hwigoda@mcs.com ("Hal Wigoda") wrote: * } > * } >A collegue of mine asked me what was the advantage in using a scroll * } >cursaor versus using an array of rowid in building a query. * } * } A scroll cursor can deal with zillions of rows -- an array has a finite * } limit on it's size. * } * } Rowid's may cause problems on 7.x engines, where it's possible that they * } may not be unique. * } * } A scroll cursor takes less code to implement! * } * } The array option might actually perform better though -- Informix * } wouldn't rush off and build a big ugly temporary table like it seems to * } enjoy doing with a SCROLL CURSOR. * } * } Summary: Big tables would likely perform better with the ARRAY approach, * } but you'd have to have a HUGE array to cope with the maximum * } number of rows in your table. I don't think it'd be worth the * } effort for little tables. * } * } Regards, * } Kerry S * } ------------------------------------,------------------------------------------ * } Kerry Sainsbury, kerry@kcbbs.gen.nz | THE INFORMIX FAQ v2.4 Oct 95 * } Quanta Systems, Auckland | http://www.iiug.org/techinfo/faq/ * } New Zealand. Work: +64 9 377-4473 | ftp://ftp.iiug.org/pub/informix/faq * } Home: +64 9 279-3571 | ftp://kcbbs.gen.nz:/pub/informix/ * } * * -perryd (Guru) * * ==================================================================== * = Perry Dillard - Chief Architect Direct Dial: (206)517-6430 = * = FourGen Software, Inc. FAX: (206)522-0054 = * = FourGen Building Tech. Support: (800)444-3398 = * = 115 NE 100th Street Sales: (800)333-4436 = * = Seattle, W.A. 98125-8098 = * = = * = e-mail: perryd@fourgen.com Web Site http://www.fourgen.com = * = = * = Home Page: http://www.geocities.com/SiliconValley/3198 = * ==================================================================== Thanks, ----------------------------------------------------------------------------- Robert Minter Data Systems Support Senior Software Engineer A Client Technologies Company E-Mail: rob@dssmktg.com Tel: 714.771.0454 #include <disclaimer.h> Fax: 714.771.3028 De Colores - Emmaus OC-13 http://www.dssny.com