Connect Mysql with PHP application

For connection with MySQL, mysqli_connect() function is used in PHP.

Syntax:
mysqli_connect(server, username, password, databasename);

Parameters Details:

server: The host name running database server. If not specified then default value is localhost:3306.
username: The username accessing the database.
password: The password accessing the database.
databasename: Mention your Database name.

It returns a MySQL link identifier on success, or FALSE on failure.

For Closing Database connection, mysql_close() function is used in PHP.

Syntax:
 mysql_close ( resource $link_identifier );

It returns TRUE on success and FALSE on failure.

Following code describes the opening and closing connection of MySQL with php.

<?php
 define('DB_SERVER', 'localhost:3306');
 define('DB_USERNAME', 'root');
 define('DB_PASSWORD', '');
 define('DB_DATABASE', 'db_doctor_appointment');
 $con = mysqli_connect(DB_SERVER,DB_USERNAME,DB_PASSWORD,DB_DATABASE);
if(! $con ) {
      die('Could not connect: ' . mysql_error());
   }
   echo 'Connected successfully';
   mysql_close($conn);
?>