Nested for loop problem

[zrodimel]

Hi, first of all thanks in advance for the help. I'm a newbie college student and am having a little problem with a project for a class that I can't figure out.

I'm trying to construct a loop that creates an array for a javascript image gallery. First I call for the categories and I want to then pull all the images from that category into the array and then loop through all the categories in the database. The code below just cycles through the first category and then quits after pulling the images from that category.

        <?php
        // SQL Query for Categories
            $sql="SELECT CategoryID, CategoryName FROM pro2category";
            $result = mysql_query($sql);
            
            if(empty($result))
            {
                $num_results = 0;
            }
            else
            {
                $num_results = mysql_num_rows($result);
            }
        
        ?>
        <?php                                
        for($i=0; $i<$num_results; $i++)
        {
            $row = mysql_fetch_array($result);
            
            $CategoryID = $row["CategoryID"];
            $CategoryName = $row["CategoryName"];

        ?>
        
        
            var <?php echo $CategoryID ?> = new Array();
            
      <!-- Images inside Array -->
      <!-- Images inside Array -->
      <!-- Images inside Array -->
      <!-- Images inside Array -->
            
            <?php
                $sql="SELECT ImageID, ImageName, ImageNumber, URL, CategoryID FROM pro2image WHERE CategoryID='$CategoryID'";
                $result = mysql_query($sql);
                
                if(empty($result))
                {
                    $num_results = 0;
                }
                else
                {
                    $num_results = mysql_num_rows($result);
                }
                
            ?>
            
                <?php                                
                for($i=0; $i<$num_results; $i++)
                {
                    $row = mysql_fetch_array($result);
                    
                    $ImageID = $row["ImageID"];
        
                ?>
                
                <?php echo $CategoryID ?>Array[<?php echo $i ?>] = "http://cgtweb2.tech.purdue.edu/356/zrodimel/Project2/admin/upload/<?php echo $ImageID ?>.jpg";
            
                <?php
                }
                ?>
            
            

        <?php
        }
        ?>

thanks for the help

Zach

[PeejAvery]

First off, always remember that you should do your best to query a database as few times as possible. This is key for maximum performace.

So, you really only want two queries in this instance.

• First query to get the category names. Store this in a PHP array.
• Second query to get all the images' data into a PHP array.

From there, you can read the first array to determine into what category to put this data. Personally, I'd use a multidimentional array with the image categories as the first dimension index. Then, the second dimension could be all the individual image data. Here's an example.

array(
  "Headshot" => array(
    array(id, name, number, url),
    array(id, name, number, url)
  ),
  "Landscape" => array(
    array(id, name, number, url),
    array(id, name, number, url)
  ),
  "Strobist" => array(
    array(id, name, number, url),
    array(id, name, number, url)
  )
)