From sfaroult@oriole.com Mon, 04 Feb 2002 11:06:59 -0800 From: Stephane Faroult Date: Mon, 04 Feb 2002 11:06:59 -0800 Subject: Re: Which is more efficient For vs FORALL Message-ID: MIME-Version: 1.0 Content-Type: text/plain Rick_Cale@teamhealth.com wrote: > > Hi DBAs > > Here are 2 scenario's. Which one is more efficient? > Assume 10,000 records to update > > Thanks > Rick > > 1. For each record update field1 with subsquery > Assume cursor is declared > FOR cursor_rec IN new_patients_cur LOOP > UPDATE > SET field1 = > (SELECT value > FROM table > WHERE ...) > WHERE .... > END LOOP; > > 2. For each record load nested table with data then update all records with > a single FORALL > > t_type1 IS TABLE OF table1.field1%TYPE; > v_type1 t_type1(10000); > > /* Load the PLSQL nested table */ > FOR cursor_rec IN new_patients_cur LOOP > v_loop_ctr := v_loop_ctr + 1; > v_type1 := cursor_rec.field1; > END LOOP; > > /* INSERT all 10,000 records with on context switch */ > FORALL v_count IN 1...10000) > UPDATE field1 = v_type1(v_count); > Give it a try, with SET TIMING ON. No such thing as seeing to believe. -- Regards, Stephane Faroult Oriole Ltd -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Stephane Faroult INET: sfaroult@oriole.com Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru@fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).