它没有连接到数据库它显示一些错误[重复]

Question

This question already has an answer here:

• Warning: mysqli_query() expects at least 2 parameters, 1 given. What? 2 answers

show some error

        <?php 
        session_start();
        $hostname = "localhost";
        $username = "root";
        $password = "";
        $dbname = "student_information_management";
        $con = mysqli_connect($hostname, $username, $password) or die(mysqli_connect_error());
        if ($con) {
         mysqli_select_db($dbname) or die(mysqli_connect_error());
         }

it's warning me Warning: mysqli_select_db() expects exactly 2 parameters, 1 given in C:\xampp\htdocs\std_management_system\config.php on line 9

</div>

Answer 1

Please read documentation for mysqli_select_db. In procedural style, you have to provide following parameters to function:

link: Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()

dbname: The database name.

Example:

mysqli_select_db($con, $dbname);