The difference between two types of open things in php mysqli extension

I see there are two ways to implement things in the documentation, one is:

<code>$link->autocommit( FALSE );//关闭自动提交

$link->query( 'sql...' );
$link->query( 'sql...' );
...
$link->commit()
</code>

One is:

<code>$link->begin_transaction();//显示声明开始事物
$link->query( 'sql...' );
$link->query( 'sql...' );
...
$link->commit();</code>

Are there any similarities or differences between these two implementation methods?