RE: what is the fastest way to update a big table with more than 50000 rows and 20 columns

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From: Cale, Rick T (Richard) <RICHARD.T.CALE_at_saic.com>
Date: Wed, 31 Oct 2001 05:24:32 -0800
Message-ID: <F001.003B911D.20011031044523@fatcity.com>

UPDATE join a
SET a.source = (SELECT b.source

                        FROM cs b
                        WHERE b.totid = a.totid);

Rick

-----Original Message-----
Sent: Wednesday, October 31, 2001 7:15 AM To: Multiple recipients of list ORACLE-L rows and 20 columns

      hi guys,
      i have a big problem in updating an oracle 8i 1.7 database table with

more than 50000 rows and 20 columns. The problem is: i have another table with approximately 17000 rows and 12 columns. The latter one holds newer data, and most of them have the same primary key as the previous one (16000). Now, i want to update the older table with newer data from the new table. I wrote a pl/sql procedure to achieve this task, but it takes too long ( nearly 12 hours) ,

can you have a look at the below procedure and tell me what is wrong with it and where i am making mistake? CAn you suggest me a faster and more efficient way to do that?

      thanks alot for your help in advance.
      cheers :)
      my Pl/sql procedure :
      ********************
      declare
      cursor c1 is
      select c.totid,j.source from join j,cs c where j.source is not null
      and trim(j.totid)=trim(c.totid);
      --join is the new table (17700 rows)
      --cs id the older one (50300rows)
      tot cs.TOTID%type;--totid is the primary key for both tables
      src cs.source%type;--source is the column to be updated
      begin
      open c1;
      loop
      fetch c1 into tot,src;
      tot:=trim(tot);
      exit when c1%notfound;
      update cs set source=src where trim(totid)=tot;
      end loop;
      commit;
      close c1;
      end;

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Author: Cale, Rick T (Richard)
INET: RICHARD.T.CALE_at_saic.com

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