Which is more efficient For vs FORALL

From: <Rick_Cale_at_teamhealth.com>
Date: Mon, 04 Feb 2002 10:28:07 -0800
Message-ID: <F001.0040527E.20020204101537@fatcity.com>

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 <table> 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);

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Received on Mon Feb 04 2002 - 12:28:07 CST