PHP - Efficient Website Design?

Okay so i have an image gallery script that creates two links, "Next Image" and "Previous Image". The script works but i'd like to know if i could make it more efficent with a better SQL query.

Here's my database



What i am currently doing is querying the database and getting a list of all the image id's in the same gallery, and putting them into an array. Which doesn't seem very logical (but it's the only solution i could come up with).

Code: [Select]
// CREATE AN ARRAY WITH ALL THE IMAGE ID'S IN THE GALLERY
//
$query = ("SELECT id FROM images WHERE gallery_id=(SELECT gallery_id FROM images WHERE id='".$_REQUEST['id']."') ORDER BY id DESC");
$result = mysql_query($query);
$images_in_gallery = array();

while ($row = mysql_fetch_array($result))
{
array_push($images_in_gallery, $row['id']);
}

And then searching through said the array to get the id of the next image and the previous image.

Code: [Select]
// CREATE THE LINK
//
$next_link = "<a href=\"?id=".$images_in_gallery[array_search($_REQUEST['id'], $images_in_gallery)+1]."\">$next_text</a>";
$prev_link = "<a href=\"?id=".$images_in_gallery[array_search($_REQUEST['id'], $images_in_gallery)-1]."\">$prev_text</a>";

Is there a way i can do this easier with a better query, for example a query that selects the next image in the gallery and the previous, i am not brilliant with SQL but i do know that if you have a good query your code can be considerably shorter.

The full code can be found here on pastebin.
http://pastebin.com/GzTpq6Uj

Hi guys, I want to find the most efficient way of setting a php variable through a link. What I'm trying to achieve is to allow the user to select a category and their location and store the two variables to update my database results.  I first used the GET method, but since the page refreshes when the user selects any other Get variable, so it ends up reseting the variables.  Currently I have the category and locations as drop down menu with links to each of the options.  I'll appreciate any help.  Thank you. :]

Hi all,


I've been trying to improve the speed of my file download script and was wondering if anyone could advise me which of the following is more efficient (Don't worry its not the whole script, just one segment), in terms of speed and server load?

The way I have the segment currently:

//if file exists need to check authorision levels

//set access to no

$access = NULL;

//retrieve current user levels

$cpm = $_SESSION['MM_CPMGroup'];

$cpmh = $_SESSION['MM_CPMHGroup'];

$cm = $_SESSION['MM_CMGroup'];

$cj200 = $_SESSION['MM_CJ200Group'];

$cj = $_SESSION['MM_CJGroup'];

//set file category type & set access if allowed

if ($category == 'cpm') {

if ($cpm == '1') {

$access = 1;

if ($subcategory == 'techdata') {

$path = "files/techdata/cpm/";

}

elseif ($subcategory == 'msds') {

$path = "files/techdata/cpm/msds/";

}

elseif ($subcategory == 'symbols') {

$path = "files/symbols/cpm/";

}

else {

$path = "files/cpm/";

}

}

}

elseif ($category == 'cpmh') {

if ($cpmh == '1') {

$access = 1;

if ($subcategory == 'techdata') {

$path = "files/techdata/cpmh/";

}

elseif ($subcategory == 'msds') {

$path = "files/techdata/cpmh/msds/";

}

elseif ($subcategory == 'symbols') {

$path = "files/symbols/cpmh/";

}

else {

$path = "files/cpmh/";

}

}

}

elseif ($category == 'cm') {

if ($cm == '1') {

$access = 1;

if ($subcategory == 'techdata') {

$path = "files/techdata/cm/";

}

elseif ($subcategory == 'msds') {

$path = "files/techdata/cm/msds/";

}

elseif ($subcategory == 'symbols') {

$path = "files/symbols/cm/";

}

else {

$path = "files/cm/";

}

}

}

elseif ($category == 'cj200') {

if ($cj200 == '1') {

$access = 1;

if ($subcategory == 'techdata') {

$path = "files/techdata/cj200/";

}

elseif ($subcategory == 'msds') {

$path = "files/techdata/cj200/msds/";

}

elseif ($subcategory == 'symbols') {

$path = "files/symbols/cj200/";

}

else {

$path = "files/cj200/";

}

}

}

elseif ($category == 'cj') {

if ($cj == '1') {

$access = 1;

if ($subcategory == 'techdata') {

$path = "files/techdata/cj/";

}

elseif ($subcategory == 'msds') {

$path = "files/techdata/cj/msds/";

}

elseif ($subcategory == 'symbols') {

$path = "files/symbols/cj/";

}

else {

$path = "files/cj/";

}

}

}

if ($access < 1) {

// if user access not granted to file category return message

if($logging > 0){

$status = "Wrong Permissions";

include('logit.php');

}

if (! $_SESSION['PrevUrl']) {

//header("Location: ". $loginpage );

exit;

}

$redirect = $_SESSION['PrevUrl'];

header("Location: ". $redirect );

exit;

}

// if file exists and user access granted continue


Obviously the above is a lot of lines of code... So I have rewritten the above to look like:


//if file exists need to check authorision levels & retrieve current user levels

if ($category == 'cpm' && $_SESSION['MM_CPMGroup'] == '1') {

$access = 1;

} elseif ($category == 'cpmh' && $cpmh = $_SESSION['MM_CPMHGroup'] == '1') {

$access = 1;

} elseif ($category == 'cm' && $cm = $_SESSION['MM_CMGroup'] == '1') {

$access = 1;

} elseif ($category == 'cj200' && $_SESSION['MM_CJ200Group'] == '1') {

$access = 1;

} elseif ($category == 'cj' && $_SESSION['MM_CJGroup'] == '1') {

$access = 1;

} else {

$access = NULL;

}

if ($access == NULL) {

// if user access not granted to file category return message

$status = "Unauthorised";

include('logit.php');

header("Location: ".$_SESSION['PrevUrl']);

exit;

}

// if file exists and user access granted continue

switch($subcategory) {

case "techdata":$path="files/techdata/".$category."/".$filename; break;

case "msds":

$path="files/techdata/".$category."/msds/".$filename; break;

case "symbols":

$path="files/symbols/".$category."/".$filename; break;

default:

$path="files/".$category."/".$filename;

}


The second version is a lot shorter, but is it better? And could I shorten the if statement further so its more like:


//if file exists need to check authorision levels & retrieve current user levels

if (($category == 'cpm' && $_SESSION['MM_CPMGroup'] == '1') || ($category == 'cpmh' && $cpmh = $_SESSION['MM_CPMHGroup'] == '1') || ($category == 'cm' && $cm = $_SESSION['MM_CMGroup'] == '1') || ($category == 'cj200' && $_SESSION['MM_CJ200Group'] == '1') || ($category == 'cj' && $_SESSION['MM_CJGroup'] == '1') {

$access = 1;

} else {

$access = NULL;

}

if ($access == NULL) {

// if user access not granted to file category return message

$status = "Unauthorised";

include('logit.php');

header("Location: ".$_SESSION['PrevUrl']);

exit;

}

// if file exists and user access granted continue

switch($subcategory) {

case "techdata":$path="files/techdata/".$category."/".$filename; break;

case "msds":

$path="files/techdata/".$category."/msds/".$filename; break;

case "symbols":

$path="files/symbols/".$category."/".$filename; break;

default:

$path="files/".$category."/".$filename;

}


Any advice would be appreciated! Thanks!!

Hi guys,

I'm developing a website which allows people to connect and follow each other's activity (like Twitter, for example).

To simplify everything, let's say I only have 2 tables:

1. Followers

id | follower_id | id_to_follow
------------------------------------

2. Activity

id | member_id | message | time
-----------------------------------------

Let's say John is following Jane and Bob. I want to create a "news" page and display the last 20 messages from Bob and Jane, chronologically.  For small numbers, I'd do something like this:

Select everything from the Activity table, check for every entry if the member is a friend of John's (in the Followers table) and, if so, display the message, ORDER BY `id` DESC.

But, this is very inefficient, I guess, for larger numbers (I can't even think about how many queries would take to do this on a site like Twitter...).

Any ideas of how to do the same thing more efficiently?

Thank you.

Need some feedback on this loop

Tables:
Table A
Table B

Loop
Select all from A based on criteria
a. Insert into table B using row data from table A
b. Update record in table A to say that it has gone through loop to prevent future loop


Thats three MySQL queries running over and over at the same time, how bad is that for performance, is there another way?

Maybe instead of running b each time build an array with the record ids from Table A and after the loop runs to insert into Table B run another query with the IN command to loop through all of the IDs in the array and update?

This question includes MySQL, but I have a feeling the answer will involve PHP so putting it here for now. If it should be moved, feel free

Say I have a for loop that iterates through a certain amount of times and updates a value in my database EACH ITERATION thru the loop. In other words, we're connecting to the database multiple times.  Seems very inefficient, so I'd like to see if there is a better way.

Here is a basic example of the "bad" way (FYI, this code is basically reordering items after one of them moves down in the list)...

Code: [Select]
for ($a=$oldvalue+1; $a<=$othervalue; $a++) {
$sql = "UPDATE tablewithids SET
id=id - 1
WHERE id=$a";
$result = mysql_query($sql, $connection);
if (!$result) {
die("Database query failed: " . mysql_error());
} else {

}
So if $othervalue happened to be 80, then it would be 80 separate connections to the database!  I imagine it would make a lot more sense to gather the data first (into an array I presume) and then make one connection to the database an update that way, but I'm having trouble wrapping my head around how to do it based on this type of example.

Can anyone offer suggestions to help make this type of for loop code more efficient?

Hello, I'm new to PHP and I have come up with the following code for my navigation but I am sure there has to be an easier and more efficient way to do this. Someone please start me on the right path. Thanks
Code: [Select]
<?php 
//Get selected page/sub page
if (isset($_GET['page'])) {
$sel_page = $_GET['page'];
$sel_sub_page = '';
} elseif (isset($_GET['sub_page'])) {
$sel_page = '';
$sel_sub_page = $_GET['sub_page'];
      } else {
$sel_page = '';
$sel_sub_page = '';
}
?> Code: [Select]
<!--Begin Navigation-->
<ul>
<?php
//run the loop to get the page titles  
$query = "SELECT * FROM pages ORDER BY position ASC";
$page_set = mysql_query($query);
confirm_query($page_set);
while($page = mysql_fetch_array($page_set)){
echo '<li><a href="content.php?page=' . urlencode($page['id']) . '">' . $page['page_name'] . '</a></li>';
//run sub page query to see if the ul tag is needed
$query = "SELECT * FROM sub_pages WHERE page_id = {$page['id']} ORDER BY position ASC";
$sub_page_set = mysql_query($query);
confirm_query($sub_page_set); 
$sub_page = mysql_fetch_array($sub_page_set);
if ($sub_page !=''){
echo '<ul>';
}
//run the sub page loop again to display the sub page title
$query = "SELECT * FROM sub_pages WHERE page_id = {$page['id']} ORDER BY position ASC";
$sub_page_set = mysql_query($query);
confirm_query($sub_page_set); 
while($sub_page = mysql_fetch_array($sub_page_set)) {
echo '<li><a href="content.php?sub_page=' . urlencode($sub_page['id']) . '">' . $sub_page['page_name'] . '</a></li>';
}
//run the sub page loop for the last time to see if the end ul tag is needed
$query = "SELECT * FROM sub_pages WHERE page_id = {$page['id']} ORDER BY position ASC";
$sub_page_set = mysql_query($query);
confirm_query($sub_page_set); 
$sub_page = mysql_fetch_array($sub_page_set);
if ($sub_page !='') {
echo '</ul>';
}
}
?>
</ul>
<!--End Navigation-->

$ch = curl_init();
////////////////////////////////////
////////////////////////////////////
for($cwb=1; $cwb!=$Amount; $cwb++)
  {
  $action = file_get_contents($Game."refresh_stat_manual?user_id=".$Keys[0]."&auth_key=".$Keys[1]);
  $xml = simplexml_load_string($action);
  foreach($xml->xml->viewer->user as $stats)

    {
    $energy=$stats->energy;
    $level=$stats->level;

}
  if($energy <= 0 || $Stop <= $level) { echo "REACHED EITHER LEVEL $Stop OR... YOU ARE OUT OF ENERGY...\n"; sleep(100000);  }
  $send1 = $Game."send_requests?user_id=".$IDone."&to_user_ids=".$Keys[0]."&auth_key=".$AuthOne;
  curl_setopt($ch, CURLOPT_URL, $send1);
  curl_exec($ch);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
  $send2 = $Game."send_requests?user_id=".$IDtwo."&to_user_ids=".$Keys[0]."&auth_key=".$AuthTwo;
  curl_setopt($ch, CURLOPT_URL, $send2);
  curl_exec($ch);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
  $accept = $Game."accept_all_mob_requests?user_id=".$Keys[0]."&auth_key=".$Keys[1];
  curl_setopt($ch, CURLOPT_URL, $accept);
  curl_exec($ch);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
  $job = $Game."do_job?user_id=".$Keys[0]."&job_id=7200018&auth_key=".$Keys[1];
  curl_setopt($ch, CURLOPT_URL, $job);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
  $exec1 = curl_exec($ch);
  if(stristr($exec1, 'You gained 6') || stristr($exec1, 'You gained 1') || stristr($exec1, 'ambulance'))
  { echo "#$cwb: <-- You've gained 1 ambulance... Level - ".$level." ::: ENERGY - ".$energy." :::\n"; }
  for($abc =1; $abc!=2; $abc++){
  $remove1 = $Game."remove_mob_member?user_id=".$Keys[0]."&remove_user_id=".$IDone."&auth_key=".$Keys[1];
  curl_setopt($ch, CURLOPT_URL, $remove1);
  curl_exec($ch);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);}
  for($abc =1; $abc!=2; $abc++){
  $remove2 = $Game."remove_mob_member?user_id=".$Keys[0]."&remove_user_id=".$IDtwo."&auth_key=".$Keys[1];
  curl_setopt($ch, CURLOPT_URL, $remove2);
  curl_exec($ch);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);}
  $sell = $Game."buy_item?user_id=".$Keys[0]."&item_id=32&amount=".$Amount."&auth_key=".$Keys[1];
  curl_setopt($ch, CURLOPT_URL, $sell);
  $exec2 = curl_exec($ch);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
  if(stristr($exec2, 'sold'))
  { echo "::: You've sold 1 ambulance...\n"; }
  }
curl_close();



Any idea on how I could make this faster or what I could change to make it to more efficient

Hi, I hope this belongs to the right sub-forum. I'm gonna be on the move for quite some time, and I was wondering if there was an [almost] ideal portable PHP development environment, which I can treat just like the non-portable counterpart, which will include using Composer, Laravel, etc.   With a little research I found http://zwamp.sourceforge.net/ and http://www.codelobster.com, but I'm not sure how efficient they are. Any of you guys use this approach?     Thanks.

Right now I am using code such as this:

$query = "SELECT somevalue FROM sometable WHERE id=1"
$result = mysql_query($update) or die ('Error in query: ' . mysql_error());

$somevalue = '';

if (mysql_num_rows($result) == 1)
  {
  while($row = mysql_fetch_assoc($userstatsresult))
    {
    $somevalue = $row['somevalue'];
    }
  }

echo $somevalue;

Is there a short-hand method to get that single value without the IF/WHILE stuff?

http://www.phpfreaks.com/forums/index.php/topic,308549.0.html

The above link is a problem relating to CSS. The way route i've choosen thanks to haku is to determine the users browser then let php give one css or another.

What is the best way to determine the users browser. At the moment i can only find a problem with css fixed in ie6 and below. Therefore i only really need to find if the user is running on ie6.

I've come accross the http://php.net/manual/en/function.get-browser.php but requires http://browsers.garykeith.com/downloads.asp.

Is there a simpler way?

I have dozens of tables that a client needs to download through the web. I can use PHP to convert the tables within the database to a CSV however I have to split the files into 10k result chunks otherwise the server gets overloaded with memory.

I already raised the memory limit within the script that is downloaded (ini_set('memory_limit', '512M') which is able to make this happen.

Downloading these files piece by piece is a really time consuming. Is there a memory safe and efficient way to combine all my tables as CSV's and into one zip them into one master download? PHPMyAdmin seems to do this smoothly, however, I need an online interface for the client to export the data directly...

currently using
function gen_chars($length = 6) {
    // Available characters
    $chars = '0123456789abcdefghjkmnoprstvwxyz';

    $Code  = '';
    // Generate code
    for ($i = 0; $i < $length; ++$i)
    {
        $Code .= substr($chars, (((int) mt_rand(0,strlen($chars))) - 1),1);
    }
return $Code;
}

// Usage
$var = gen_chars(12);

echo $var;

However ide like to know if theres a more efficient way of generating this since this is going to be using a lot.

Thanks