Question

In this code I am trying to search a database with two columns, retrieve 11 pairs of those based on one of the matches (companyname; this was sent from JavaScript using POST). Then I am trying to create a JSON data.

<?php
header("Content-Type: application/json");
$db = new PDO('mysql:host=localhost;dbname=pl;charset=UTF-8', 'user', 'password');
if(isset($_POST['companyname']) == true && empty($_POST['companyname']) == false) {

    $searchterm = $_POST['companyname'];
    $i=0;
    $jasondata = '{';

    $query = $db->query("SELECT companyname, axiscategory FROM axispl WHERE companyname LIKE '$searchterm%' LIMIT 11");
    $c = 1;
    while (($row=$query->fetchAll(PDO::FETCH_ASSOC)) !==false && $c<11) {
        $i++;
        $companyname = $row["companyname"];
        $axiscategory = $row["axiscategory"];
        $jasondata .='"combi'.$i.'":{"companyname":"'.$companyname.'","axiscategory":"'.$axiscategory.'"},';
        $n=$row['companyname'];
        $l=strlen($n);
        if($l>50){$c = $c+2;}else{$c = $c+1;}       

    }
    $jasondata = chop($jasondata, ",");
    $jasondata .= '}';
    echo $jasondata;

}   
?>

Answer 1

What should you change? Well, I mentioned using json_encode earlier, and Charles quite rightly points out the security vulnerability.

I’d also work on the code formatting as well – my recommendation is to work to a sensible margin. This used to be 80 characters for historical reasons, but 100-120 is quite a good limit now – it means you can have several code viewers stacked left-to-right on your screen without the need to scroll horizontally in each one. And you can post to StackOverflow similarly without wrapping issues!

Consider this snippet of yours:

$query = $db->query("
    SELECT
        companyname, axiscategory
    FROM
        axispl
    WHERE
        companyname LIKE '$searchterm%'
    LIMIT 11
");

Also:

$db = new PDO(
    'mysql:host=localhost;dbname=pl;charset=UTF-8',
    'user',
    'password'
);

Much more readable, eh? My motto: give your code room to breathe.