MySQL resource, fetch(), and looping - php

Question

i had a headache over the last few days trying to understand this snippet of code. it's about retrieving data from a database table nothing hard (i'm using mysql) . but i'm trying to understand the code. here is the code:
<?php
include 'PDOconnect.php';
//Query
$result = $connection->query('SELECT * FROM video_games');
//Fetch
$data = $result->Fetch();
while ($data = $result->Fetch()) {
echo $data['name']."<br />";
}
?>
first let me explain, the second line is including the connection code to the database i'm using the PDO way of connecting. the connection is fine . my table is called video_games and it had a column called 'name'. and i'm trying with this code to retrieve all the data from the column 'name'.
1- so what i want to understand is what is the $result variable (line 6) , i've heard it's a Resource. what a resource in mysql means, and what's inside of the variable $result is it the whole table or what exactly ??
2- what the function fetch() does ?? it's confusing .
3- what i know from studying the basic syntax of php is that inside the while condition
the value must be true in order to execute the code inside.
but here there is ($data = $result->Fetch()) .
4- is the fetch() method automatically incremented ?? i mean why it is working successfully inside the while condition, so it must be incrementing over and over again ??
please help my mind is blowing right now.

Answer 1

$result is not a Resource,. it's a PDOStatement. see the docs: http://www.php.net/manual/en/pdo.query.php
Once a PDOStatement is executed (automaticalyl using ->query()) the statement holds the result the database returned.
Everytime you ->fetch() it returns the current row the Statement is pointing to. After that it points it pointer to the next row (so yes, 'automatically incremented).
Now, your code:
Everything inside if and while statements is evaluated using loose comparision (==)
if ( $a ) actually checks or $a == true.
$data = $result->fetch() simply sets a value to $data. Then the while checks or $data == true. IF so, it does what it has to do. (see php == vs === operator for more about comparisons in php)
Now, a little remark on your code: the first row is not outputted since you don't do anything with the first fetched result. Simply remove
//Fetch
$data = $result->Fetch();
So your code would become:
<?php
include 'PDOconnect.php';
//Query
$result = $connection->query('SELECT * FROM video_games');
while ($data = $result->Fetch()) {
echo $data['name']."<br />";
}
A good tutorial about PDO: http://net.tutsplus.com/tutorials/php/why-you-should-be-using-phps-pdo-for-database-access/

Answer 2

1 what is the $result variable
It is not a resource. It's actually an object of PDOStatement class
2 what the function fetch() does ?? it's confusing.
A manual page is always at your service. Just type PDO fetch in the browser's address bar and click the first link opened. It is extremely easy and no less powerful.