Class to Cache?

[rcbasie]

Hi
I'm doing a lot of reading and wondering at the mo - got to move our website over to PHP and MySQL, but it's gonna be difficult to do this without changing the structure and layout. One possibility i thought of is to cache certain queries, the only question being how i could implement this. I think i could achive this with the use of some classes which would store database values in (multidimensional) arrays, and have scripts get these values from the class, to reduce load on the database. The classes would be able to return the array values via a method, and also have methods to periodically re-query the database and store the results in it's member variable. I would then hold only one instance of this class in a kind of 'container function' that i could define and include in a separate file.
Has anyone ever done something like this before? Is this a recognised technique, and if so is there any examples or documentation that could help me in the design? You may well be able to guess that i'm fishing a bit here, i could be proposing the impossible!?!
Thanks in advance for any responces
Robin

[van__]

Sounds like an .ini file is what you really need here.. though classes are nice, I see no need for an object to be born just to hold dumb data.

You can set up an ini file like so:

[element1]
key1=value1
key2=value2
...
[element2]
key1=value1
key2=value2
...

...and so on ad nauseum

You use ;'s as comments...
;;this is a comment

No need to have anything but a line break to end your lines.

now to read it...
<?
$ini = parse_ini_file($ini_file_path, TRUE);
//and here's your hash table
print_r($ini);
?>

[Anon]

No problem. Take a look at serialize(), unserialize(), etc.

Write the variables you want to a string, save to disk.

Objects do not survive through multiple page views, so you have to write to disk and then read, unserialize, then return the variable data.

I'd base the database query on the time since last file write - see filemtime or filectime depending on your methods. For even better performance, fork a background process to update the cache files on page load, rather than load db, write to file, then return results.

The use of a class to store variables can make sense if you feel that there may be name collisions. For example, I commonly use an object in my work, (usually called $CONF) that contains site-specific values that I know cannot cause name collisions with the root namespace, my functions, etc.

Just try to keep it simple and consistent - define methodologies and problem-solving procedures first, rather than code - and I'm sure your migration will go smoothly - as a consultant I've done this sort of a thing a few times 😉