am I using massive resource for sending mySQL qurey through PHP?

[Yousef Al-Hadhrami]

Hello dear mySQL users
I have been using mySQL for only ~2 weeks so I am a noob :D, please be gentle on me as this is my first post too.

what I want to ask about is that I have wrote 2 functions that will auto arrange a unique number field in a column
ofcourse global $current_page; is an array that used mysql to read whole row
and global $connection; is the connection string

<?php
function rearrange_position($modify_position_to){
global $current_page;
global $connection;
$current_page_id = $current_page['id'];
$current_page_position = $current_page['nav_position'];

if($current_page_position > $modify_position_to){
while($current_page_position > $modify_position_to){
$query = "UPDATE pages SET ";
$query .= "nav_position = '{$current_page_position}' ";
$current_page_position--;
$query .= "WHERE nav_position = '{$current_page_position}' ";
mysqli_query($connection, $query);
}
} elseif ($current_page_position < $modify_position_to){

while($current_page_position < $modify_position_to){
$query = "UPDATE pages SET ";
$query .= "nav_position = '{$current_page_position}' ";
$current_page_position++;
$query .= "WHERE nav_position = '{$current_page_position}' ";
mysqli_query($connection, $query);
}
}
}
?>
thats the function and this is the implementation
<?php
// Perform Update

$id = $current_page["id"];
$page_name = mysql_prep($_POST["page_name"]);
$nav_position = (int) $_POST["nav_position"];
$visible = (int) $_POST["visible"];

// reorder function start
rearrange_position($nav_position);
// reorder function end

$query = "UPDATE pages SET ";
$query .= "page_name = '{$page_name}', ";
$query .= "nav_position = {$nav_position}, ";
$query .= "visible = {$visible} ";
$query .= "WHERE id = {$id} ";
$query .= "LIMIT 1";
$result = mysqli_query($connection, $query);
if($result)....// you know the remaining, if query sucess
show a message , else echo query failed
?>

and I have another function for arranging that deals when inserting a new row and when deleting a row..

the question is when each time I change a row I use a new query and it's limited to how many rows in the table
I was thinking of saving all of desired rows id's to be changed then change each ones nav_position(the unique column) using an array and only type one long mySQL query

or the current one I am using is fine?
thank you, please if you are not sure what to replay, just post your function for arranging unique columns. :)

// pss is there a way to make my code appear more readable in the forum?