So far so good. You've connected to the DB...

Is the deletion business logic simple enough to be done in a single DML statement? For example...

DELETE from TABLENAME T where T.SOMEDATE <= (sysdate() - 7) and T.FREEFLAG = TRUE;

I don't know mysql so I'm giving a generic kind of syntax here... If the issue is not that simple, then you need to issue an appropriate SELECT statement, capture the results in perl, analyze them, and then issue delete statements on the appropriate rows... I haven't used the DBI in a while, so I don't remember the exact syntax of passing DML statements to the DBI, but in PERL, the results of the statement can be captured automatically in an array... Again I'm going to illustrate with "pseudo syntax". You translate into something that actually works...

$statement_to_exec = "SELECT X,Y,Z from T where Z...;"
(@myARRAY) = $myconnect->execute($statement_to_exec);

Now suppose you have properly set up your select statement so that the data comes out like this....

A,B,C
D,E,F
G,H,I

etc... That is, fields separated by commas (just as an example) and each record on its own line... So guess what.... $myARRAY[0] = "A,B,C" and $myARRAY[1] = "D,E,F" etc. That is each record is put in a separate element of @myARRAY! I'm assuming here that you've left perl's default line ending character alone, that the lines end with that (usual) character, etc. You can control all of this, but usually it isn't necessary....

OK, so now you can iterate over each line...
while ($line = shift @myARRAY) { ... logic here ... }

And then, you can split line into it's separate fields with....

($field1, $field2, $field3) = split /,/ , $line;

Now $field1 = "A", $field2 = "B", etc.

This is how you proceede... When you decide which lines must be deleted, say the line in $myARRAY[2] (the third line), then you issue a DELETE via the DBI for that line only....

As for the cron line, that is very easy. Just edit a file in your home directory called myCRONTAB (sysadmins might want you to use a system CRONTAB, or some other established one) and put a line in it like....

0 0 * * * /path/to/your/script.pl (says run at 0 min of 0 hr every day, I'll let you look up cron syntax for yourself)...

Then set up the job by entering cron myCRONTAB and if there are no syntax errors in the file, your good to go...

Oh... One more thing to remember.... when you run a script from cron it has NO ENVIRONMENT... So, you can't rely on PATH, or anything else. You have to set all that stuff up in your perl script....

Long I know, but I hope it helps....