As I stated in the section that you just read, the best way to understand how this MySQL abstraction layer can be used consists of developing an illustrative example that shows the real capacity offered by the bridge pattern.

In response to this, below I coded a pair of short scripts. They first connect to MySQL using the respective "MySQL" class that you saw before, and then use the "mysqli" library for accessing the database server. Here are the corresponding code samples:

// example using the 'MySQL' class

try{

	// instantiate 'BridgeMySQLConnector' class

	// connect to MySQL using 'MySQL' wrapping class

	$bmysqlcon=new BridgeMySQLConnector

('host','user','password','database','mysql');

	// run query using 'MySQL' wrapping class
   
	$bmysqlcon->query('SELECT * FROM users');
}

catch(Exception $e){

	echo $e->getMessage();

	exit();
}

try{

	// example using the 'mysqli' extension

	// connect to MySQL using 'mysqli' library
 
	$bmysqlcon=new BridgeMySQLConnector

('host','user','password','database','mysqli');

	// run query using 'mysqli' library
  
	$bmysqlcon->query('SELECT * FROM users');
}

catch(Exception $e){

	echo $e->getMessage();

	exit();
} 

See how easy it was to connect to MySQL using either the wrapping class or the "mysqli" extension? I bet you do! In both cases, I also executed a "SELECT" statement against a hypothetical "USERS" database table, but logically this condition can be easily modified to run other SQL commands.

As you saw, learning how to apply the bridge design pattern with PHP was indeed an enjoyable experience, right?

Final thoughts

At this point, it's quite probable that you have learned the fundamentals of using the bridge design pattern with PHP 5. Personally, I consider this pattern to be very useful for decoupling a class from its implementation, if for some reason abstract classes are not a viable approach.

Besides, its versatility allows you to apply it in a great variety of cases. Therefore I recommend that you keep it at hand if you want to achieve a high level of abstraction with your PHP-based applications. See you in the next PHP tutorial!