PHP site URL ID please Help! - php

Question

Please could someone help im building my first website that pulls info from a MySQL table, so far ive successfully managed to connect to the database and pull the information i need.
my website is set up to display a single record from the table, which it is doing however i need some way of changing the URL for each record, so i can link pages to specific records. i have seen on websites like facebook everyones profile ends with a unique number. e.g. http://www.facebook.com/profile.php?id=793636552
Id like to base my ID on the primary key on my table e.g. location_id
ive included my php code so far,
<?php
require "connect.php";
$query = "select * from location limit 1";
$result = #mysql_query($query, $connection)
or die ("Unable to perform query<br>$query");
?>
<?php
while($row= mysql_fetch_array($result))
{
?>
<?php echo $row['image'] ?>
<?php
}
?>
Thanks

Answer 1

Use $_GET to retrieve things from the script's query (aka command line, in a way):
<?php
$id = (intval)$_GET['id']; // force this query parameter to be treated as an integer
$query = "SELECT * FROM location WHERE id={$id};";
$result = mysql_query($query) or die(mysql_error());
if (mysql_num_rows($result) == 0) {
echo 'nothing found';
} else {
$row = mysql_fetch_assoc($result);
echo $row['image'];
}

Answer 2

There are many things to consider if this is your first foray into MsSQL development.
SQL Injection
Someone might INSERT / DELETE, etc things via using your id from your url (be careful!, clean your input)
Leaking data
Someone might request id = 1234924 and you expected id = 12134 (so some sensitive data could be shown, etc;).
Use a light framework
If you haven't looked before, I would suggest something like a framework (CodeIgniter, or CakePHP), mysql calls, connections, validations are all boilerplate code (always have to do them). Best to save time and get into making your app rather than re-inventing the wheel.

Answer 3

Once you have selected the record from the database, you can redirect the user to a different url using the header() function. Example:
header('Location: http://yoursite.com/page.php?id=123');

Answer 4

You would need to create a link to the same (or a new page) with the URL as you desire, and then logic to check for the parameter to pull a certain image...
if you're listing all of them, you could:
echo "" . $row['name'] . ""
This would make the link.. now when they click it, in samepage.php you would want to look for it:
if (isset($_GET['id']) && is_numeric($_GET['id'])) {
//query the db and pull that image..
}

Answer 5

What you are looking for is the query string or get variables. You can access a get variable through php with $_GET['name']. For example:
http://www.facebook.com/profile.php?id=793636552
everything after the ? is the query string. The name of the variable is id, so to access it through your php you would use $_GET['id']. You can build onto these this an & in between the variables. For example:
http://www.facebook.com/profile.php?id=793636552&photo=12345
And here we have $_GET['id'] and $_GET['photo'].

Answer 6

variables can be pulled out of URL's very easily:
www.site.com/index.php?id=12345
we can access the number after id with $_GET['id']
echo $_GET['id'];
outputs:
12345
so if you had a list of records (or images, in your case), you can link to them even easier:
$query = mysql_query(...);
$numrows = mysql_num_rows($query);
for ($num=0;$num<=$numrows;$num++) {
$array = mysql_fetch_array($query);
echo "<a href=\"./index.php?id=". $row['id'] ."\" />Image #". $row['id'] ."</a>";
}
that will display all of your records like so:
Image #1 (links to: http://www.site.com/index.php?id=1)
Image #2 (links to: http://www.site.com/index.php?id=2)
Image #3 (links to: http://www.site.com/index.php?id=3)
...