Information about database connection.

[LilPlant]

Friends, I have created a simple user registration system but encountering an error when connecting to the database. The error message is: Fatal error: Uncaught Error: Call to undefined function mysql_select_db() in D:\xampp\htdocs\uyekayit\kayit.php:2 Stack trace: #0 {main} thrown in D:\xampp\htdocs\uyekayit\kayit.php on line 2. The code written on line 2 is: mysql_select_db("deneme", mysql_connect("localhost","root"));