date calculations

[Ninjakreborn]

I have something that I find myself doing quite a bit, but I end up doing it the same way everytime.  I have a number, for instance 30.  I need it to go down daily, like if 3 days go by, I need it to be 27, and so forth until it hit's 0, then I can do something with it.  Like a timeperiod of how long something can be active.  The thing is I always record the date like 09-11-06 or something in the database, this is the date that the item, or whatever was entered into the database, then I have the current date.  I use something, like I decide when is the best imte, like right when they log in, or right when a specific page is open.  Then I check the date, turn it into a timestamp, record todays date, turn it into a timestamp, compare them, do some calculations, to make the date update, and that's it.  Then I go back, and above that, do a check for the 0 or less value, so it doesn't run unnecessary calculations, and instead either deletes the item, or moves it into another table for old items, or something, this would be whatever, a use with a timelimit on a paid account, or the lifetime of the post for a classified system.  does anyone know of a better way to do this, or a place I can put the information to run the script, somewhere that won't kill the server.  Because if I check all the entries in all the database, and update them all everytime someone logs in, or visits the site, then it might kill the server if a lot of people hit the site at once.  I don't really want that happened, and hoenstly, that many database calls at that many times, can calls db rewrites, and a lot of other things, and make the information in accurate. Or it could end up doing it 2-3 times before it updates the number, and make the number over-update. I am thinking of checking an individual users posts everything he/she logs into the site.  Then I also have the problem of people who create accounts, put some posts down then never come back to the site, they never get deleted.  Should I check each post individually.  Like if someone is browsing posts, go ahead and check then, or does anyone have another way of doing this, any advice, opinions are welcome, I have to do something to return a number of day's left, that's the whole point.

[ober]

Please.... for our own sanity... if you're going to ramble for that long, break it up with a few presses of the "Enter" key from time to time.  No one wants to read a giant hunk of text like that.

[hostfreak]

Got half away through that before I started to get a headache. I'll come back and read the other half after I recover. Hopefully then I will be able to offer some advice.

[AndyB]

[quote]I always record the date like 09-11-06[/quote]

Is that day month year, or month day year, or year month day, etc.  I bet you'll find doing anything with dates that it's simpler to use yyyy-mm-dd [the ISO standard date format] in your database. 

You can, of course, re-present dates drawn from the database in any format you want.

And Ober's right. Split it up into coherent thoughts in paragraphs. Make this stuff easier for us to read!!!!

[Ninjakreborn]

It's set up like month-date-year
I have it formatted in the databas,e I can save it however, if it's better then I will start saving it in that format.

The thing I was wondering was, is there another way to do calculations, or is there a good place to put the program to keep it from overloading the server, if a lot of people get it to do the same thing everytime.