AJAX va ma’lumotlar bazasi
AJAX ma’lumotlar bazasi bilan interaktiv aloqa uchun ishlatilishi mumkin.
AJAX ma’lumotlar bazasi misoli
Quyidagi misol veb-sahifa qanday qilib AJAX yordamida ma’lumotlar bazasidan ma’lumot olishi mumkinligini ko‘rsatadi:
Misol tushuntirmasi - showCustomer() funksiyasi
Agar foydalanuvchi yuqoridagi ochiladigan ro‘yxatda mijozni tanlasa, showCustomer() funksiyasi bajariladi. Funksiya onchange hodisasi tomonidan ishga tushiriladi:
showCustomer
function showCustomer(str) {
if (str == "") {
document.getElementById("txtHint").innerHTML = "";
return;
}
const xhttp = new XMLHttpRequest();
xhttp.onload = function() {
document.getElementById("txtHint").innerHTML = this.responseText;
}
xhttp.open("GET", "getcustomer.php?q="+str);
xhttp.send();
}
showCustomer() funksiyasi quyidagilarni bajaradi:
- Mijoz tanlanganligini tekshirish
- XMLHttpRequest obyektini yaratish
- Server javobi tayyor bo‘lganda bajariladigan funksiyani yarating
- So‘rovni serverdagi faylga yuboring
- E’tibor bering, URL’ga (ochiluvchi ro‘yxat tarkibi bilan) parametr (q) qo‘shiladi
AJAX server sahifasi
Yuqoridagi JavaScript tomonidan chaqirilgan serverdagi sahifa "getcustomer.php" deb nomlangan PHP faylidir.
"Getcustomer.php" dagi manba kodi ma’lumotlar bazasiga qarshi so‘rovni bajaradi va natijani HTML jadvaliga qaytaradi:
<?php
$mysqli = new mysqli("servername", "username",
"password", "dbname");
if($mysqli->connect_error) {
exit('Could not connect');
}
$sql = "SELECT customerid, companyname,
contactname, address, city, postalcode, country
FROM customers WHERE
customerid = ?";
$stmt = $mysqli->prepare($sql);
$stmt->bind_param("s", $_GET['q']);
$stmt->execute();
$stmt->store_result();
$stmt->bind_result($cid,
$cname, $name, $adr, $city, $pcode, $country);
$stmt->fetch();
$stmt->close();
echo "<table>";
echo "<tr>";
echo "<th>CustomerID</th>";
echo
"<td>" . $cid . "</td>";
echo "<th>CompanyName</th>";
echo "<td>" . $cname
. "</td>";
echo "<th>ContactName</th>";
echo "<td>" . $name . "</td>";
echo "<th>Address</th>";
echo "<td>" .
$adr . "</td>";
echo "<th>City</th>";
echo "<td>" . $city . "</td>";
echo "<th>PostalCode</th>";
echo "<td>" .
$pcode . "</td>";
echo "<th>Country</th>";
echo "<td>" . $country .
"</td>";
echo "</tr>";
echo "</table>";
?>
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