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Editorial Team
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Asked: 2026-05-14T15:39:40+00:00

I am a college student taking a course in php and mysql progamming and

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I am a college student taking a course in php and mysql progamming and my first question is about the “$variable” variables in the following code:

<?php ob_start(); ?>

<?php

session_start();

if ($_SESSION['auth'] != "true")
{ header("Location: login.php");
  exit;
}

$uid = $_SESSION['user'];

$connection = mysql_connect("localhost", "username", "password");

mysql_select_db("username", $connection);

$result = mysql_query ( "SELECT * FROM users where user_id = '$uid'", 
$connection);

$num = mysql_numrows($result);

$i=0;
while ($i < $num) {
$f1=mysql_result($result,$i,"firstname");
$f2=mysql_result($result,$i,"lastname");
?>

<html><body>
<p>
<td><center><font size = "18" face="Arial"><?php echo "Name: $f1 "; echo $f2; ?> </font></center></td>
</p>
</body></html>

<?php
$i++;
}
?>


<?php

$result1 = mysql_query ( "SELECT * FROM phone where user_id = '$uid'", $connection);

$num1 = mysql_numrows($result1);

$j=0;
while ($j < $num1) {
$f3=mysql_result($result1,$j,"type");
$f4=mysql_result($result1,$j,"number");
?>

<html><body>
<p>
<br>
<td><center><font size = "12" face="Arial"><?php echo "$f5: "; echo "($f3) "; echo "$f4 <br />"; ?> </font></center></td>
</p>
</body></html>

<?php
$j++;
}
?>

<?php

$result2 = mysql_query ( "SELECT * FROM address where user_id = '$uid'", $connection);

$num2 = mysql_numrows($result2);

$h=0;
while ($h < $num2) {
$f6=mysql_result($result2,$h,"type");
$f7=mysql_result($result2,$h,"address");
$f8=mysql_result($result2,$h,"city");
$f9=mysql_result($result2,$h,"state");
$f10=mysql_result($result2,$h,"zip");
?>

<html><body>
<p>
<br>
<td><center><font size = "12" face="Arial"><?php echo "$f10 Address: $f6, $f7, $f8 $f9"; ?></font></center></td>
</p>
</body></html>

<?php
$h++;
}
?>

<?php

include 'navbar.php';

ob_end_flush();

?>

I just don’t really understand the $variables at all. Are they user-generated or are they entities in the database? And how does the code know which $result is which?

My second question is that, if this was someone else in my class’s code and I wanted to modify it to make it my own and substitute my own variables, how would I go about doing that? Do the $variables need to be changed if they are not user-defined and if so, how? I apologize if these are dumb questions, but I am a beginner at this programming language. Thanks in advance for your help.

-Jeff

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1 Answer

  1. Editorial Team

    In PHP you don’t need to define the variables and neither the var type. That’s mean that the variable declaration is implicit in any new assignment.
    The $ symbol it’s used by PHP to understand that it’s a variable.

    An example:

    $result = mysql_query ( "SELECT * FROM users where user_id = '$uid'", $connection);

    With this line you do basically 3 things:

    1. Define a new variable called $result
    2. Set the variable type based on the result type of your function a resource in this case
    3. Assign the function’s result to the variable.

    you can learn more about PHP variables and types on php.net, could be interesting for you also read more about === operator

    next time, could you please use the code tag in your post ? 🙂

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