POST action

<form action="action.php" method="post"> <p>Your name: <input type="text" name="name" /></p> <p>Your age: <input type="text" name="age" /></p> <p><input type="submit" /></p> </form>In the PHP tutorial manual, it says that we can have post action to the form itself just like above coding.I would like to know in the real projects, can we have action to the same PHP file, since that we only need have one filebut not 2 files foe POST request,Your help and information is great appreciated,regards,Iccsi,