Using plugin API

Hello, guys. TodayI will show how to use functions from anotherplugin on your server.
Firstly, we will get this plugin.

PHP:

$this->pl=$this->getServer()->getPluginManager()->getPlugin("MyPlugin");

Than, for example, want make mysql connections for our plugins.
And we will make one thing in onEnable() function:

PHP:

$this->mysqli=new \mysqli("ip", "user", "password", "database");

But we know, that some users have limit of mysql connections to mysql database.
So with this function we can make 1 connection for 2 plugins.
But how?
To do this, we must have in second plugin some function, that uses mysql. Example getParticle()

PHP:

public function getParticle($player){
   $player=strtolower($player);
   $result = $this->pl->mysqli->query("SELECT FROM `table` WHERE `nick` = "'.$player.'"");
   $data=$result->fetch_assoc();
   return $data['particle'];
}

That we used mysql function from another plugin to use mysql or second plugin.