How to work with two MySQl databases?

Question

PHP

Always worked with one DB (MySQL). Now it was required to make a selection from a table in one database, and then from a table in another. What is the best way to organize it?
Now, in each file where there are requests, the code from the mysql.php file is "included" at the beginning

$hostname='localhost';
$username='root';
$password='';
$basename='base1';
mysql_connect($hostname, $username, $password) or die (mysql_error());
mysql_select_db($basename) or die (mysql_error());
mysql_query("set character_set_client	='utf8'");
mysql_query("set character_set_results	='utf8'");
mysql_query("set collation_connection	='utf8_general_ci'");

But now I have 2 bases. Surely it should?

$hostname='localhost';
$username='root';
$password='';
mysql_connect($hostname, $username, $password) or die (mysql_error());
//вызов mysql_select_db в этом месте важен?
mysql_query("set character_set_client='utf8'"); 
mysql_query("set character_set_results='utf8'");
mysql_query("set collation_connection='utf8_general_ci'");


mysql_select_db('base1') or die (mysql_error());
//запросы к этой базе

mysql_select_db('base2') or die (mysql_error());
//запросы к этой базе

How to work with two MySQl databases?

Answer 1

Probably yes))) Works? I would make two connections, it's more convenient, or select the base before each request. As I understand it, the task is educational, so any option is acceptable.
In real projects, they make different connections and use OOP.