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-   -   Hopefully a straightforward PHP/MySQL question (http://www.daniweb.com/forums/thread123209.html)

antwan1986 May 8th, 2008 10:52 am
Hopefully a straightforward PHP/MySQL question
 
Hi everyone and thanks for reading!

I have a MySQL database with a table called "lessons". Inside lessons there are about six or seven fields holding information about piano lessons. The table looks like this:

vid          int(10) (Primary Key)
title        varchar(50)
date        date
teaser        varchar(500)
description        varchar(2000)
vurl        varchar(50)
extra        varchar(1000)

All I'm wanting to do is retrieve these values and place them where I'd like, so I know the code to do that through the SELECT statement WHERE vid = and then the paramater I pass in the URL.

At the moment I only have one record, so the vid=1 and this works fine. What I'm wanting to do is make a bit of PHP that stops people trying to access records that don't exist, like vid=33 and so on. At the moment it loads the page and displays no values (because there is no record 33!) but i'd rather it realised there was no record 33 and brought up a message saying sorry there is no such record. I've made one that catches if they've removed the ?vid like so:

$vid = $_GET['vid'];
if (!$vid) { echo "<h2>We've Encountered A Problem</h2>\n"; };
die;

Can anyone help me catch these records that don't exist?

Anthony

robothy May 8th, 2008 11:07 am
Re: Hopefully a straightforward PHP/MySQL question
 
Hey,

If you run the SQL select query to find a vid record, if it returns no rows, which you can find using mysql_num_rows(), display the error message.

R.

antwan1986 May 8th, 2008 11:24 am
Re: Hopefully a straightforward PHP/MySQL question
 
Quote:

Originally Posted by robothy (Post 602802)
Hey,

If you run the SQL select query to find a vid record, if it returns no rows, which you can find using mysql_num_rows(), display the error message.

R.



Hi and thanks for your quick reply. I looked that function and came up with the following, which works brilliantly.

if (mysql_num_rows($result) == 0) { die("Uh-oh.."); };

Thank you very much, you're a life saver.

Anthony


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