my sql code for DOB

hai...in phpmyadmin data base table my DOB is coming in adding foramt...did i need to change the type...???

my code in php format:

 $DOBMonth = false;
if(isset($_POST['DOBMonth'])){
    $DOBMonth = $_POST['DOBMonth'];
 }

$DOBDay = false;
if(isset($_POST['DOBDay'])){
    $DOBDay = $_POST['DOBDay'];
 }

$DOBYear = false;
if(isset($_POST['DOBYear'])){
    $DOBYear = $_POST['DOBYear'];
 }


$DateOfBirth=$DOBMonth+"/"+$DOBDay+"/"+$DOBYear;