Is there a better loop I could write to reduce database queries? - php

Question

Below is some code I've written that is effective, but makes too many database queries. Is there a way I could optimize and reduce the number of queries but have conditional statements still be as effective as below?
I pasted the code repeated a few times just for good measure.
echo "<h3>Pool Packages</h3>";
echo "<ul>";
foreach ($items as $item):
$this->db->where('id', $item['id']);
$query = $this->db->get('items')->row();
if ($item['quantity'] > 1 && $item['quantity'] == TRUE && $query->category == "Pool Packages") {
$newprice = $item['quantity'] * $query->price;
$totals[] = $newprice;
}
else {
$newprice = $query->price;
$totals[] = $newprice;
}
if ($query->category == "Pool Packages") {
echo "<li>" . $query->name . " (QTY: " . $item['quantity'] . " x = " . str_ireplace(" ", "", money_format('%(#10n', $newprice)) . ")</li>";
}
else { }
endforeach;
echo "</ul>";
echo "<h3>Water Features</h3>";
echo "<ul>";
foreach ($items as $item):
$this->db->where('id', $item['id']);
$query = $this->db->get('items')->row();
if ($item['quantity'] > 1 && $item['quantity'] == TRUE && $query->category == "Water Features") {
$newprice = $item['quantity'] * $query->price;
$totals[] = $newprice;
}
else {
$newprice = $query->price;
$totals[] = $newprice;
}
if ($query->category == "Water Features") {
echo "<li>" . $query->name . " (QTY: " . $item['quantity'] . " x = " . str_ireplace(" ", "", money_format('%(#10n', $newprice)) . ")</li>";
}
else { }
endforeach;
echo "</ul>";
echo "<h3>Waterfall Rock Work</h3>";
echo "<ul>";
foreach ($items as $item):
$this->db->where('id', $item['id']);
$query = $this->db->get('items')->row();
if ($item['quantity'] > 1 && $item['quantity'] == TRUE) {
$newprice = $item['quantity'] * $query->price;
$totals[] = $newprice;
}
else {
$newprice = $query->price;
$totals[] = $newprice;
}
if ($query->category == "Waterfall Rock Work") {
echo "<li>" . $query->name . " (QTY: " . $item['quantity'] . " x = " . str_ireplace(" ", "", money_format('%(#10n', $newprice)) . ")</li>";
}
else { }
endforeach;
echo "</ul>";
echo "<h3>Sheer Descents</h3>";
echo "<ul>";
foreach ($items as $item):
$this->db->where('id', $item['id']);
$query = $this->db->get('items')->row();
if ($item['quantity'] > 1 && $item['quantity'] == TRUE && $query->category == "Sheer Descents") {
$newprice = $item['quantity'] * $query->price;
$totals[] = $newprice;
}
else {
$newprice = $query->price;
$totals[] = $newprice;
}
if ($query->category == "Sheer Descents") {
echo "<li>" . $query->name . " (QTY: " . $item['quantity'] . " x = " . str_ireplace(" ", "", money_format('%(#10n', $newprice)) . ")</li>";
}
else { }
endforeach;
echo "</ul>";
echo "<h3>Booster Pump</h3>";
echo "<ul>";
foreach ($items as $item):
$this->db->where('id', $item['id']);
$query = $this->db->get('items')->row();
if ($item['quantity'] > 1 && $item['quantity'] == TRUE && $query->category == "Booster Pump") {
$newprice = $item['quantity'] * $query->price;
$totals[] = $newprice;
}
else {
$newprice = $query->price;
$totals[] = $newprice;
}
if ($query->category == "Booster Pump") {
echo "<li>" . $query->name . " (QTY: " . $item['quantity'] . " x = " . str_ireplace(" ", "", money_format('%(#10n', $newprice)) . ")</li>";
}
else { }
endforeach;
echo "</ul>";
echo "<h3>Pool Concrete Decking</h3>";
echo "<ul>";
foreach ($items as $item):
$this->db->where('id', $item['id']);
$query = $this->db->get('items')->row();
if ($item['quantity'] > 1 && $item['quantity'] == TRUE && $query->category == "Pool Concrete Decking") {
$newprice = $item['quantity'] * $query->price;
$totals[] = $newprice;
}
else {
$newprice = $query->price;
$totals[] = $newprice;
}
if ($query->category == "Pool Concrete Decking") {
echo "<li>" . $query->name . " (QTY: " . $item['quantity'] . " x = " . str_ireplace(" ", "", money_format('%(#10n', $newprice)) . ")</li>";
}
else { }
endforeach;
echo "</ul>";
echo "<h3>Solar Heating</h3>";
echo "<ul>";
foreach ($items as $item):
$this->db->where('id', $item['id']);
$query = $this->db->get('items')->row();
if ($item['quantity'] > 1 && $item['quantity'] == TRUE && $query->category == "Solar Heating") {
$newprice = $item['quantity'] * $query->price;
$totals[] = $newprice;
}
else {
$newprice = $query->price;
$totals[] = $newprice;
}
if ($query->category == "Solar Heating") {
echo "<li>" . $query->name . " (QTY: " . $item['quantity'] . " x = " . str_ireplace(" ", "", money_format('%(#10n', $newprice)) . ")</li>";
}
else { }
endforeach;
echo "</ul>";
echo "<h3>Raised Bond Beam</h3>";
echo "<ul>";
foreach ($items as $item):
$this->db->where('id', $item['id']);
$query = $this->db->get('items')->row();
if ($item['quantity'] > 1 && $item['quantity'] == TRUE && $query->category == "Raised Bond Beam") {
$newprice = $item['quantity'] * $query->price;
$totals[] = $newprice;
}
else {
$newprice = $query->price;
$totals[] = $newprice;
}
if ($query->category == "Raised Bond Beam") {
echo "<li>" . $query->name . " (QTY: " . $item['quantity'] . " x = " . str_ireplace(" ", "", money_format('%(#10n', $newprice)) . ")</li>";
}
else { echo "<li>None</li>"; }
endforeach;
echo "</ul>";
It goes on beyond this to several more categories, but I don't know how to handle looping through this best. Thanks!

Answer 1

You could build the html in a variable so you only loop once. Here's a quick and dirty example just to show you what I'm talking about:
$html = '';
$oldCat = '';
foreach ($items as $item) {
$this->db->where('id', $item['id']);
$query = $this->db->get('items')->row();
if ($oldCat != $query->category) {
$html .= "</ul>\n";
$html .= "<h3>".$query->category."</h3>\n<ul>\n";
$oldCat = $query->category;
}
if ($item['quantity'] > 0) {
$newprice = $item['quantity'] * $query->price;
$totals[] = $newprice;
}
$html .= "<li>" . $query->name . " (QTY: " . $item['quantity'] . " x = " . str_ireplace(" ", "", money_format('%(#10n', $newprice)) . ")</li>\n";
}
// strip leading /ul, append a /ul, echo html

Answer 2

You could store all the rows into a separate array during the first loop and then reference the array throughout all the other loops rather than fetching the same information over and over, assuming you're select * which you probably are.
Or, if there are not many items more than the ones you're fetching, you could use a single query to fetch all of the rows at once (you're using only one query) and loop through that to store all the values in an array $array[$row['id']] = $row (or something similar) then simply reference all those rows in the array in each of your loops.

Answer 3

You need to start thinking in terms of sets instead of loops. Write a stored proc that takes the array either as a varchar (or in SQL Server 2008 you can use a table valued input parameter, don't know about other dbs).
Then split the string into a temp table and return all the records in one select joining to the temp table. Even if you need to return separate record sets, doing it in a stored proc will reduce the network traffic in.

Answer 4

you should use a join from items to category and get all the items, then you can sort them out into a multi-dimensional array and then loop through that for output.
Im not sure what youre classes db connection is doing but but lets assume we want all items with thier category:
$sql = "SELECT item.*, category.name as category from item, category WHERE item.category_id = category.item_id";
// ill use PDO for db access here...
$db = new PDO($connString, $username, $password);
$items = array(); // our array indexed by category.
foreach($db->query($sql) as $item) {
if(!array_key_exists($items, $item['category']) {
$items[$item['category']] = array();
}
$items[$item['category']][] = $item;
}
// now loop through $items using the similar stuff you did for output previously.
// note instead of doing the conditionals for pricing and stuff here you may want to
// do that in the loop above and put it in the array before hand... it will keep the
// output loop cleaner.