Update table content every 24 hours

[crighton]

Hi,

I'm looking for some basic guidance on the best method to automate the following task:

1) Pull some basic data / image from a database.
2) 24 hours later go back to database and redo the above to replace current content with new content.

I've looked around and can't find scripts close enough to the above for me to work out the best way to approach it. I know it involves two basic concepts:

1) Some sort of date / time comparison to control the 24hr update sequence (no date or timestamp is included in the Db table to be used).
2) Some way to randomly pick replacement content from the Db by id number.

Any suggestions or script samples are welcome. Not looking for any finished scripting here just pointers on how best to approach it.

Many thanks,

Gary Crighton

[eoghain]

Well if your database is on a *NIX box you can just write a cron job to take care of the 24 thing. That's what cron jobs are for.

As for randomly selecting an image, do you have a unique ID on your images table? Is your unique ID sequential? If yes on both of these you could just select the min and max values and then use them in a randomizer to select a number between the 2 and finally use that number to select your image.

If you have ID's but that aren't sequential, then you could select them all into an array (which does have sequential ID's) and again use a randomizer to get a number between 1 and the count - 1 of the array and use the ID found there.

Finally if you don't have any unqiue ID's on your table does your database keep one for you (think Oracle's rownum)? If so then you can use that. Or if your database uses the LIMIT statement you can use that by getting the count() of rows then geting a random number between 1 and the count() and finally doing a select using the random number as the OFFSET in the LIMIT statement and getting only 1 row.

Thats all I can think of now, but if none of these seem to work then post your table structure and I'll see if I can see anything.

[crighton]

Eoghain,

Well if your database is on a *NIX box you can just write a cron >job to take care of the 24 thing. That's what cron jobs are for.

Allow me to plead ignorance here - the platform is Unix / Apache / MySQL, but I have no idea what a cron job is. I have no direct access to the server itself as this is a standard commercial hosting package. If a cron job refers to a script that I can run on a server under those conditions then great, I can look into that as an option. If that's not likely to be available to me then I'll need to look at some other way of measuring a 24 hour time span.

As to the Db table there are in fact two. All images (they are artworks) have a unique ID but these are not sequential, so creating some form of array based on those ids as you suggest looks good.

Thanks for your advice,

Gary

[eoghain]

Talk with your hosting company and see if they will allow you a shell account and a cron job. Cron is a UNIX deamon that runs around the clock and kicks off processes at specified times that you decide. Since you want this to run once a day you can set it up to run your script every night at midnight. But you will probably need shell access to your host, unless they have set something else up. And if PHP is only installed as an Apache module then you will need either Lynx (or some other text browser) installed on the host machine, or you will have to write your script in another language.