| Re: Multiple <a> Tags, Filled With MySQL DB data with PHP [message #179232 is a reply to message #179220] |
Tue, 25 September 2012 18:41   |
Denis McMahon
Messages: 634
Registered: September 2010
Karma:
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Senior Member |
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On Tue, 25 Sep 2012 10:43:45 -0700, tom.rankin51 wrote:
> I am trying to create two image galleries using fancybox. There is no
> issue doing this by manually typing out a bunch of <a> tags with the
> info inside, but when I attempt to code a piece of PHP to pull this data
> from my database, it doesn't like it and displays the images strangely.
Basic troubleshooting for php / mysql / html stuff:
1) Turn all the warnings on in php
2) Make sure that every database call tests for errors, and that they get
reported
2a) In extreme cases, output the actual sql query and var_dump the result:
I do something like this at the top of my code in such situations:
<?php
$debugtxt = "";
$debugging = false;
if ( $_SERVER['REMOTE_ADDR'] == $my_ip && $_GET['debug'] == "37" )
$debugging = true;
?>
and wrap something like this round every sql call:
<?php
$sql = ".......";
$result = mysqli->query( $sql );
$debugtxt .= "sql call to get date of last login from users table\n";
$debugtxt .= "sql: {$sql}\n";
$debugtxt .= "Result:" . var_dump( $result );
if ( $result === false ) {
...... do onething
}
else {
...... do otherthing
}
?>
When you generate the html, before the closing </body> tag:
<?php if ( $debugging ) echo "<hr><h1>Debugging</h1><pre>$debugtxt</pre>
\n"; ?>
3) check the server error logs after each request
4) view the html source of the pages you get so you can see the actual
html that your page is generating
5) When posting to the group, pare your code down to the minimum that
demonstrates the problem.
You will hopefully then be able to determine where your code is going
wrong and why.
In this particular case, I would suggest (4) is particularly important,
you have told us what you expect, and what code you use to generate it,
but have not shown us what the generated html looks like when examined
with the source viewer in your browser.
If no html is generated, go back to the server logs looking for a php
reported error. If your sql query is failing, your sql result set is
actually the value false, and you're failing to detect this. There may be
an sql error message in your server logs.
Rgds
Denis McMahon
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