help with pl/sql

Hi, all
I have a situation here, I have a table called messagearchive,which grows too big too fast,
SQL> desc messagearchive;
Name Null? Type
----------------------------------------- -------- ----------------------------
MSGID NOT NULL CHAR(16)
SERVICEID NOT NULL CHAR(16)
MSGTEXT VARCHAR2(4000)
MSGDATE NOT NULL DATE

based on our business requirements, we only need to keep two(latest) msgtexts for each serviceid. I can do it in a very clumsy way, which is that I do a
select unique(serviceid),max(msgdate) from messagearchive group by serviceid; and put it into a temp table, and get results by joining messagearchive and temp and put it into temp_messagearchive table and then truncate table messagearchive and put back the data from temp_messagearchive to messagearchive.
I know there must be a better way to do it, but I just can not come up with it. I would appreciate if anyone can help me out with PL/SQL packages to do the same job. Thanks for help.

Dragon

Try a before insert trigger. Check if there are two message text in there already. If there is don't insert.

Quote:

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Originally posted by lesstjm
Try a before insert trigger. Check if there are two message text in there already. If there is don't insert.

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In the Before Insert Triger:

IF NoOfMessage >= 2 THEN
delete ones which has not the latest date on it;
insert into the new message;
ELSE
insert into the new message;
END IF;

Thanks for the advice. But do you think it would be too expensive to place a trigger on it on the performance side? because there are at least of 100,000 messages were inserted into that table. I have no idea which one is more efficient, put on trigger on it, or insert a delete later( with 100,000 records inserted every day).