| Re: Multiple <a> Tags, Filled With MySQL DB data with PHP [message #179238 is a reply to message #179232] |
Tue, 25 September 2012 19:58   |
tom.rankin51
Messages: 17
Registered: September 2012
Karma:
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Junior Member |
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I'm not too sure how to debug correctly following these instructions. I can place the code at the beginning and end of my page, but I am getting a syntax error when typing $result = mysqli->query($sql);
Also, I'm unsure which bits I place around which other other bits :-D This is something which is taking me completely out of my depth to be honest so even though the description was in depth, it's maybe not as in depth enough for me.
Tom
On Tuesday, September 25, 2012 7:41:38 PM UTC+1, Denis McMahon wrote:
> 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;
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> 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
>
> }
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> else {
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> ..... do otherthing
>
> }
>
>
>
> ?>
>
>
>
> When you generate the html, before the closing </body> tag:
>
>
>
> <?php if ( $debugging ) echo "<hr><h1>Debugging</h1><pre>$debugtxt</pre>
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> \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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