I have images being stored in folders related to articles on my PHP web site, and would like to set the order to display the images based on author input. I started by naming the files with a number in front of them, but was considering recording the order in a text file instead to avoid renaming every file and retaining their original file names, or possibly storing the order in a MySQL table.
My question is about best practice and speed - every time the article is loaded, it will have to find out the order of images to display them. I was hoping to get some input about which method would be best and fastest.
For example, is it much slower to read a list of file names in a folder with PHP, or open a text file and read the contents, compared to making MySQL query and update statements?
I'd say a lot depends on your base hardware/filesystem/mysql connection performances. A single access to disk, just to read images is most likely going to be your quickest option. But you'd need to name your files manually ahead.
Mysql requires a TCP or *NIX socket connection, and this might slow down things (a lot depends on the number of pictures you have, and the "quality" of your db link, though). If you have a lot of files, performance hit might be negligible. Just reading from a file might be quicker nevertheless, without bothering to set up a DB connection; you'd still have to write down ID/filename correspondence for the ordering though.
Something I'd try out in your situation is to take a look at the php stat command, and see if it can help you out sorting the pictures. Depending on the number of pictures you have (it works better with lower numbers), performance might not get a serious performance hit, and you'd be able NOT to keep a separate list of picture/creation date tuples. As your number of pictures grow, the file list approach seems to me like a reasonable way to solve the problem. Just benchmarking the thing as the number of pictures increases can tell you the truth, though. Since, I think, you can expect to have lot of variability, depending on your specific context.
imho, using mysql would be slower, but oh so much easier. if the mysql server is hosted on the same server (or within dedicated space on the same server, like cloud linux), then it probably wont save too much time
edit
if you want to do a test, you can use the microtime function to time exactly how long it takes to append and sort the files, and how long it takes to get it all from mysql
if your concern is performance why don't you save the list (maybe already formatted in HTML) to a file. When your page is loaded just read the file with
$code = file_get_contents("cache_file.html")
and output to the user. The fastest solution is to store the file as .html and let apache serve it directly, but this works only if your page doesn't have any other dinamic part.
to ensure that your cache file is up to date you can make it invalid and recreate it after some time (the specific time depends from the frequency in image changes) or check if the directory is changed after the cache file creation date. If you can trigger the changes in the image directory (for example if the changes are made from a piece of code that you wrote you can always ensure that you cache is refreshed when the images are changed)
Hope this helps
This smells like premature optimization.
My question is about best practice and speed - every time the article is loaded, it will have to find out the order of images to display them.
So? A query like "select filename, title from images where articleId=$articleId order by 'order'" will execute within a fraction of a second. It really doesn't matter. Do whatever is the easiest to do, and might I suggest that being the SQL option.