automatic data update

onionjohn

hi all
i am trying to build a utility that will retrieve the latest data from the backend, display it to the user, and update automatically if any changes are made to the database.

that probably isn't all too clear, so here is a simple example: suppose there is one record in the db "abcd" -> as soon as someone changes that to "efgh", the user witnesses the update without doing anything.

now i've figured out a few of ways to do this (implemented a few of these, have confidence that i would be able to do the others):
1. simple browser refresh
2. iframe/frame with browser refresh
3. update DIV content using javascript (replaces innerHTML with reference to appropriate PHP file)
4. applet streams data from MySQL
5. flash streams data from MySQL

now the question... is there any other way to do it? i know that seems like an odd question to ask since there are so many ways to do it as shown above, but it's a long story. 🙂

i appreciate any help that anyone out there could give. i hope i was clear enough. thanks in advance!
-jaspal-

csaba

Another way that I sometimes use is to open a (possibly modal) window whose source is a php file. I use this when the user might not already by logged in, in which case he gets the modal login dialog. Upon success the information is returned to the modal dialog. If no login is necessary, I bypass the login screen and get the info back to the modal dialog. In both cases when the info is returned to the modal window, it dismisses itself just after stuffing the original page with the return value (and does a setTimeout to the return routine in the opener).

Actually, I'm quite curious about the reason for your question. Please do enlighten. By the way, since mySQL doesn't have triggers, I assume that what you mean is that the user sees the changes soon after they are made rather than as soon as they are made.

Also, would you elaborate, please, a bit on your DIV content method. I'm not following how you tie the php file into the innerHTML.

Csaba Gabor

onionjohn

thanks for the response ... i'm putting this thing on pocket ie, which doesn't support multiple windows or iframe. also, i can't use an applet or flash because of non-technical reasons. the whole thing with the div, i implemented with a dynamically generated image (moot point because the div approach didn't work on PIE either, but here goes). i create a javascript function that - using the setTimeout method - calls itself. in this method, i write a div element and set the innerhtml of the div on each call to the function. within the div, i am calling an img of the form "<img src=image.php". so the image keeps getting refreshed - any changes to that php file will be registered and the setTimeout fn refreshes that part of the screen appropriately. the whole image thing was just a placeholder - i was gonna try to figure out a way to write just the data to the div element (don't know if this was possible or not). in any case, i gave up as soon as i realized it wouldn't work on PIE (no support for DHTML DOM).

and yeah, after the update to mysql takes place, i want the user to be able to see it. 🙂

csaba

Hi again,

I appreciate the elaboration.  I'm familiar with the <img src=image.jpg?data=passed+passed+to+server as a way to get data to the server (I use this as a way to get images scaled to fit a target window - the fake image.jpg is actually a .php program which parses the GET argument) without the DIV.
But what I didn't understand from your explanation was how you get back USABLE information (unless you are inserting it into the header as a cookie).  In other words, and the reason for my question, is there a way you can get back parseable data (> 2K) using this method?
As I'm writing this it occurs to me that in the div you could possibly set a <script src= which is what would drag in the new information.  That's probably what you were talking about.

Regards and good luck,
    Thanks for the idea,
          Csaba