Convert MySQL query loop to PHP array (table) - php

Question

I have a system which looks through a database, creates a table of a specified size and then fills the cells with either full or empty depending if there is data in the database for that specific location.
At the moment it works by doing a SQL query for each cell and then populating, but I have 30,000+ records in the database and even with a LIMIT 1 it's still taking about 5 second to load the table.
I'm wondering if dumping the entire contents into a PHP array and then querying that way would be better, but can't work out the best way to sort it, any tips welcome.
Current (working) code:
echo <<<EOD
<table class="racktable"><tr>
<td colspan ="$colspan">Rack Details </td>
</tr>
<tr>
<td colspan ="$colspan"><center>Edit Rack / Empty Rack / Delete Rack</center> </td>
</tr>
EOD;
//Loop through rows, creating a <tr> for each in the table
for ($row1 = 1; $row1 <= $rows; $row1++) {
echo <<<EOD
<tr><td><a name="$row1"></a>$row1</td>
EOD;
//Loop through columns creating <td> within <tr>
for ($col1 = 1; $col1 <= $columns; $col1++) {
$sql2 = "SELECT ID, sample, rack, srow, col, location FROM samples WHERE srow = $row1 and col = $col1 and location = '$location' and rack = '$rack' LIMIT 1";
if (!$result2 = $db->query($sql2)) {
die('There was an error running the query [' . $db->error . ']');
}
$row3 = $result2->num_rows;
//If location is empty, colout green
if ($row3 == 0) {
echo "<td style=\"background-color: #A3CD81\">" . $col1 . "</td>";
}
else {
//Location is not empty, colour red and link to sample
while ($row2 = $result2->fetch_assoc()) {
$columns1 = $row2['col'];
$ID = $row2['ID'];
$tooltip = $row2['sample'];
$queryStr = $_SERVER['QUERY_STRING'];
$spath = $_SERVER['PHP_SELF'] . "?" . $queryStr . "&sample=" . $ID;
echo <<<EOD
<td style="background-color: #FF0000" title="$tooltip">$col1 <img src="icon.png" style="border: 0" alt=""></td>
EOD;
}
}
}
echo "</tr>";
}
echo "</table>";

Answer 1

You can convert all data from DB directly into a php array with this code:
while(($PHPToPHP[] = mysql_fetch_assoc($SqlResult )) || array_pop($dataToPHP));
may be work for your code:
while(($dataToPHP[] = $result2->fetch_assoc()) || array_pop($dataToPHP))
And to see what it does use print_r($dataToPHP).
To manage the errors die('There was an error running the query [' . $db->error . ']'); and if ($row3 == 0) { echo "<td style=\"background-color: #A3CD81\">" . $col1 . "</td>";} to colorize, you need to make some tests to correctly manage.

Answer 2

You need an array with index like your where
SELECT ID, sample, rack, srow, col, location
FROM samples
WHERE srow = $row1 and col = $col1 and location = '$location' and rack = '$rack'
LIMIT 1";
Your array looks like:
$samples = array(
"$row1:$col1:$location:$rack" => array( 'id' => $id, 'sample' => $sample
)
Or you can use some hash array like:
$samples = array(
md5( "$row1:$col1:$location:$rack" ) => array( 'id' => $id, 'sample' => $sample
)
Insert all values once - than get it like
$val = $samples["$row1:$col1:$location:$rack"];
// or from hash array
$val = $samples[md5( "$row1:$col1:$location:$rack" )];