how do I modify this ff database?!?

jennyp

Can anyone can help me with this routine. It's probably embarrassingly simple but I'm not very far ahead with PHP, so I would appreciate some help.

I have a flat-file database, which contains a record of titles for pictures. Its lines are like:

1|This is a caption for a picture|
2|This is another caption for a picture|
3|This is yet another caption for a picture|

...and so-on. I'm trying to write some PHP code which will allow a user to change those caption titles in the database. So, I'm trying a form, which takes the number of the caption to be changed, and the new text for the caption, like this:

<form id="catmanageform" action="processcatalogue1.php" method="post">
Enter Picture Number to change:<br />
<input type="text" name="picnumbertochange" size="3" maxlength="3">
<br /><br />
Enter New Text Description:<br />
<input type="text" name="pictexttochange" size="50" maxlength="50">
<br /><br />
<input type="submit" name="proccat1Button" value="Submit New Values">
</form>

This sends to "processcatalogue1.php", and it's here that I'm getting stuck.

So far I have:

<?php
$CurrentPicNumber = $POST['picnumbertochange'];
$CurrentPicNewText = $POST['pictexttochange'];
$Database = fopen('/...serverpath.../database.txt', "w");

...Now I want to read the Database in, insert the new values for the caption from the form, and then write it out again (overwrite it). I've done this before where the HTML form actually included all the values of the database, so in that case was easy: the user just changed selected values from all the values, as required, clicked send, and so the whole 'new' database was read in, and then written back. But here I was hoping to do it by only changing the single selected "number and text" pair. But I'm conceptually flummoxed! Can anyone help?

justsomeone

I haven't done a lot of work on flat file databases, but here is my suggestion, since no-one else has responded.

Open the file using "r" mode so that you can read the contents.
Open a new temp file using "w".

Then using a loop, read in each line of the original file and check if it's the one you want to change. If this is the line to be changed, change it, and write it to the temp file. Otherwise just write it to the temp file. At the end of the loop, close both files, and copy the new one in place of the old one.

This method could prove unusable if multiple people want to edit at the same time.

Now might be a good time to consider looking at a database such as mysql.

Then you need to

jennyp

That's similar to what I had in mind I guess, but I'm still not sure how to code it and I could really use an example!

Installer

Example:

$CurrentPicNumber = $_POST['picnumbertochange'];
$CurrentPicNewText = $_POST['pictexttochange'];
$new_data = '';
$file_lines = file('/...serverpath.../database.txt');
foreach ($file_lines as $line) {
    list($pic_number) = explode('|', $line);
    if ($pic_number == $CurrentPicNumber) {
        $line = $pic_number . '|' . $CurrentPicNewText . '|' . "\r\n";
    }
    $new_data .= $line;
}
$fp = fopen($your_file, 'w');
fwrite($fp, $new_data);
fclose($fp);

jennyp

Installer you are a total genius! I was working on this today and I got something very like your code but yours works! Tons of thanks to justsomeone and Installer for steering me in the right direction! (happy bunny!) PS I know I should use MySQL or whatever but I've got to do this in a hurry