Solusi mengatasi Mysql_select_db() expect exactly 2 parameter 1 given

<?php
$server = "localhost";
$user = "root";
$password = "";
$database ="si jtravel";
$koneksi = mysqli_connect ($server, $user, $password) or die ("koneksi gagal");
 mysqli_select_db ($koneksi, $database) or die ("database gagal");

Makasih gan sangat membantu mau tnya lagi klo yg ini gimana

mysqli_error() expects exactly 1 parameter, 0 given in C:\xampp\htdocs\buku\config.php on line 8

$koneksi = mysqli_connect($host, "root", "") or die("cannot connect" . mysqli_error($koneksi)); mysqli_select_db($koneksi, $db_name) or die(mysqli_error($koneksi));

<div><strong>Warning</strong>: mysqli_select_db() expects exactly 2 parameters, 1 given in <strong>C:\xampp\htdocs\toko\toko\login\config.php</strong> on line <strong>7</strong><br>DBase E !<br><br>&lt;?php<br>&nbsp; &nbsp; date_default_timezone_set('Asia/Jakarta');<br>&nbsp; &nbsp; $Open = mysqli_connect("localhost", "root","","toko");<br>&nbsp; &nbsp; &nbsp; &nbsp; if (!$Open){<br>&nbsp; &nbsp; &nbsp; &nbsp; die ("MySQL E !&lt;br&gt;");<br>&nbsp; &nbsp; &nbsp; &nbsp; }<br>&nbsp; &nbsp; $Koneksi = mysqli_select_db("toko");<br>&nbsp; &nbsp; &nbsp; &nbsp; if (!$Koneksi){<br>&nbsp; &nbsp; &nbsp; &nbsp; die ("DBase E !");<br>&nbsp; &nbsp; &nbsp; &nbsp; }<br>?&gt;<br><br>caranya gimn mengatasi ini</div>