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# PHP PDO Connections [PHP PDO Reference](#) Connections are established by creating an instance of the PDO base class. The PDO class name is used regardless of which driver is used. ### Connecting to MySQL **Note:** A PDOException object will be thrown if there is any connection error. ### Handling Connection Errors query('SELECT * from FOO') as $row) { print_r($row); } $dbh = null;} catch (PDOException $e) { print "Error!: " . $e->getMessage() . "
"; die();}?> After a successful connection, an instance of the PDO class is returned to the script. The connection remains active for the lifetime of that PDO object. To close the connection, you need to destroy the object to ensure that all remaining references to it are deleted. This can be done by assigning a NULL value to the object variable. If you don't do this, PHP will automatically close the connection when the script ends. ### Closing a Connection: Many web applications benefit from using persistent connections to database services. Persistent connections are not closed at the end of the script. Instead, they are cached and reused when another script requests a connection with the same credentials. Persistent connection caching avoids the overhead of establishing a new connection every time a script needs to talk to the database, making web applications faster. ### Persistent Connections true));?> **Note:** If you want to use persistent connections, you must set PDO::ATTR_PERSISTENT in the driver options array passed to the PDO constructor. If this attribute is set using PDO::setAttribute() after the object is initialized, the driver will not use persistent connections. * * PHP PDO Reference](#)