数据未插入数据库并尝试将最相关的类别添加到产品中

I am making a CRUD for a simple home application, and for some reason, I am not able to find out what's wrong in the code. My product creation page is not creating a product, because it's not POSTing anything, on my local PHP 5.3.2 Mamp Pro environment, and online in a server it didn't work either. I tried with both the create and update pages, and nothing. As I am really NEW to OOP and rusty in PHP and mysql, I am posting the code so you can tell me what can be wrong with it.

--
-- Table structure for table `products1`
--

CREATE TABLE IF NOT EXISTS `products1` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(32) NOT NULL,
`description` text NOT NULL,
`price` int(11) NOT NULL,
`category_id` int(11) NOT NULL,
`created` datetime NOT NULL,
`modified` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY (`id`)
 ) ENGINE=MyISAM  DEFAULT CHARSET=latin1 AUTO_INCREMENT=14 ;

--
-- Table structure for table `menu`
--

CREATE TABLE IF NOT EXISTS `menu` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(255) CHARACTER SET utf8 NOT NULL,
`parent_id` int(11) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB  DEFAULT CHARSET=utf8 COLLATE=utf8_bin AUTO_INCREMENT=136 ;

<?php 
echo "<div class='right-button-margin'>";
echo "<a href='test.php' class='btn btn-default pull-right'>Ver Todos los Productos</a>";
echo "</div>";
?>
<?php
// get database connection
include_once 'config/database.php';

 $database = new Database();
 $db = $database->getConnection();
 // if the form was submitted
 if($_POST){

// instantiate product object
include_once 'objects/product.php';
$product = new Product($db);

// set product property values
$product->name = $_POST['name'];
$product->price = $_POST['price'];
$product->description = $_POST['description'];
$product->category_id = $_POST['category_id'];

// create the product
if($product->create()){
    echo "<div class=\"alert alert-success alert-dismissable\">";
        echo "<button type=\"button\" class=\"close\" data-dismiss=\"alert\"        aria-hidden=\"true\">&times;</button>";
        echo "Creamos el producto!";
    echo "</div>";
}

// if unable to create the product, tell the user
else{
    echo "<div class=\"alert alert-danger alert-dismissable\">";
        echo "<button type=\"button\" class=\"close\" data-dismiss=\"alert\"    aria-hidden=\"true\">&times;</button>";
        echo "No pude crear el producto!";
    echo "</div>";
    }
 }
 ?>
 <!-- HTML form for creating a product -->

  <form action='create_product.php' method='post'>

  <table class='table table-hover table-responsive table-bordered'>

     <tr>
        <td>Nombre</td>
        <td><input type='text' name='name' class='form-control' required></td>
    </tr>

    <tr>
        <td>Costo</td>
        <td><input type='text' name='price' class='form-control' required></td>
    </tr>

    <tr>
        <td>Descripción</td>
        <td><textarea name='description' class='form-control'></textarea></td>
    </tr>

    <tr>

<td>Categoría</td>
<td>
  <?php
   // Test connection and list  

   try {

  $objDb = new PDO('mysql:host=111.111.111.111;dbname=nat', 'nat', '123');
  $objDb->exec('SET CHARACTER SET utf8');

$sql = "SELECT * 
        FROM `menu`
        WHERE `parent_id` = 0";
$statement = $objDb->query($sql);
$list = $statement->fetchAll(PDO::FETCH_ASSOC);

 } catch(PDOException $e) {
echo 'There was a problem';
}
// end



 // read the product categories from the database
 include_once 'objects/category.php';

 $category = new Category($db);
// $stmt = $category->read();

// put them in a select drop-down DISABLED not working
/* echo '<select class="update" name="category" id="category">';
    echo "<option>Seleccioná la categoría...</option>";

    while ($row_category = $stmt->fetch(PDO::FETCH_ASSOC)){
        extract($row_category);
        echo "<option value='{$id}'>{$name}</option>";
    }


 echo "</select>";*/
  ?>
     <select name="category" id="category" class="form-control update">
        <option value="">Seleccionar Categoría</option>
        <?php if (!empty($list)) { ?>
            <?php foreach($list as $row) { ?>
                <option value="<?php echo $row['id']; ?>">
                    <?php echo $row['name']; ?>
                </option>
            <?php } ?>
        <?php } ?>
    </select>


<select name="level1" id="level1" class="form-control update"
        disabled="disabled">
        <option value="">----</option>
    </select>

    <select name="level2" id="level2" class="form-control update"
        disabled="disabled">
        <option value="">----</option>
    </select>

    <select name="level3" id="level3" class="form-control update"
        disabled="disabled">
        <option value="">----</option>
    </select>

    <select name="level4" id="level4" class="form-control update"
        disabled="disabled">
        <option value="">----</option>
    </select>

    <select name="level5" id="level5" class="form-control update"
        disabled="disabled">
        <option value="">----</option>
    </select>

    <select name="level6" id="level6" class="form-control update"
        disabled="disabled">
        <option value="">----</option>
    </select>

     </td>
 </tr>
        </td>
    </tr>

    <tr>
        <td></td>
        <td>
            <button type="submit" class="btn btn-primary">Crear</button>
        </td>
    </tr>

</table>

Besides this I want to know what is the lowest most relevant subcategory is passed to the POST, so the product is assigned to it.