I'm learning PHP and there is a piece of code that I don't completely understand

[mousico]

I took the code below from a PHP book I'm reading and I understand how it all works except 1 point that confuses me a little - I don't get how the line "while ($rows=mysql_fetch_array($results))" works. At the point in the program that $rows is tested as to whether it is equal to the recordset which is mysql_fetch_array($results), there is surely nothing in $rows yet as nothing has been assigned to it yet so how is this condition satisfied?

 

Also, mysql_fetch_array obviously takes only one record from the recordset "$results" but does it automatically move to the next record in $results with every iteration of this loop?

 

<?php

//connect to MySQL

$connect = mysql_connect("host", "user", "password") or

die ("Hey loser, check your server connection.");

 

//make sure we're using the right database

mysql_select_db ("database");

 

$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 ($rows=mysql_fetch_array($results)) {

extract($rows);

echo $movie_name;

echo " - ";

echo $movie_type;

echo "<br>";

}

 

?>

[JonnoTheDev]

while ($rows=mysql_fetch_array($results))" works. At the point in the program that $rows is tested as to whether it is equal to the recordset which is mysql_fetch_array($results),

This is not true. The = operator assigns a value, it is not a comparison. You are thinking of ==.

The mysql_fetch_array() function returns an array of data from the database query for each row. As there are more than 1 rows returned, in order to iterate through them the while loop is used.

So in simple words each row from the database is assigned to the variable $rows (should have used $row really) as an array until the end of the result set is reached.

[mousico]

Thanks for your explanation. I understand it now I think. You're right, I was comparing it to something like "While ($count == 1)" but I get it now - the assignment happens with each execution of the while line and returns a boolean of true until there are no more records? I think.

[JonnoTheDev]

correct

[iJoseph]

//connect to MySQL
$connect = mysql_connect("host", "user", "password")
or die ("Hey loser, check your server connection.");

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

 

That isn't right is it? I thought it had to be... ^{_{(Note the $conn in the database connection.)}}

$conn = @mysql_connect( "host", "username", "password" ) 
or die ( "This code fails, Fix it." );

$rs = @mysql_select_db( "Database", $conn ) 
or die ( "This code fails, Fix it." );

Then again, I'm probally wrong. But that's what I always do.

[JonnoTheDev]

you are wrong