Need This Explained

arimakidd · October 20th, 2005, 06:35 PM

I am studying php/mysql. I am migrating from asp/access combination. The code below is fairly simple and its just one part giving me problems to understand. That is the while loop. I do not understand the condition. Before the loop starts what is the value of $row and what is the value of mysql_fetch_array($results). Here is the code:

Code:

<?php
//connect to MYSQL
$connect = mysql_connect("localhost","root","newman$")
or die("Hey loser, check your server connection.");

//make sure we're using the right database
mysql_select_db("moviesite");

$query = "SELECT movie_name, movie_type " .
"FROM movie " .
"WHERE movie_year>1990 ".
"ORDER BY movie_type";
$results = mysql_query($query)
or die(mysql_error());



while ($row = mysql_fetch_array($results)) {
extract($row);
echo $movie_name;
echo " _ ";
echo $movie_type;
echo "<br>";
}

?>

I hope I can get some kind of help here.

anshul · October 21st, 2005, 12:25 AM

Before the loop starts what is the value of $row and what is the value of mysql_fetch_array($results).

Its fairly simple.

$row is nothing as not initialized before the loop.
$results points to {result set} of query to MySQL. It's an identifier.

while ($row = mysql_fetch_array($results)) says if $row is empty or if can't fetch an array from result set, exit from the loop.

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robprell · November 3rd, 2005, 10:11 PM

PHP unlike most programming languages don't require you to initialize a variable. It auto initializes the variable when you first use it. As is the case in your code. Foxpro used to allow the same type of stuff to make things easier for lazy programmers. It can sometimes be dangerous to do this though.