postgresql - cron job to remove old data from postgres on debian

Question

I need to create a cron that runs every night and remove some of the data (older ones) from my database. I am running postgres on debian. How do I do that? My server is tomcat6. Does anyone have a step by step instruction including script to do that?

Answer 1

in most cases, I prefer a shell script with an here-document. (shell-variables expand nicely in here-documents):

#!/bin/sh
PSQL=/local/postgres/bin/psql
SOME_VALUE=123

$PSQL my_database <<THE_END
DELETE FROM my_table
WHERE my_column <= $SOME_VALUE
    ;
THE_END