Notice: Undefined index: soft_id in C:xampphtdocsSLRUpdate S110 PC01.php on line 14

Notice: Undefined index: soft_name in C:xampphtdocsSLRUpdate S110 PC01.php on line 15

Notice: Undefined index: installed_date in C:xampphtdocsSLRUpdate S110 PC01.php on line 16

Notice: Undefined index: expiry_date in C:xampphtdocsSLRUpdate S110 PC01.php on line 17

Notice: Undefined index: product_key in C:xampphtdocsSLRUpdate S110 PC01.php on line 18

Fatal error: Uncaught Error: Call to undefined function mysql_query() in C:xampphtdocsSLRUpdate S110 PC01.php:22 Stack trace: #0 {main} thrown in C:xampphtdocsSLRUpdate S110 PC01.php on line 22

<?php
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "slr";

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

$soft_id = $_POST['soft_id'];
$soft_name = $_POST['soft_name'];
$installed_date = $_POST['installed_date'];
$expiry_date = $_POST['expiry_date'];
$product_key = $_POST['product_key'];

$sql = "UPDATE s110_pc01 ". "SET soft_name = $soft_name ".
              "WHERE soft_id = $soft_id" ;
$retval = mysql_query( $sql, $link );


if($retval ) {
    echo "Updated data successfullyn";
} else {
die('Could not update data: ' . mysql_error());
mysql_close($link);
}
?>
<form method = "post" action = "<?php $_PHP_SELF ?>">
                  <table width = "400" border =" 0" cellspacing = "1"
                     cellpadding = "2">

                     <tr>
                        <td width = "100">Software ID</td>
                        <td><input name = "soft_id" type = "text"
                           id = "soft_id"></td>
                     </tr>

       <tr>
                        <td width = "100">Software Name</td>
                        <td><input name = "soft_name" type = "text"
                           id = "soft_name"></td>
                     </tr>