So I'm using php and trying to echo some stuff to <select> options from database.

First I want to echo let's say all Cars to the first <select> (I can do this) but then I want to echo the SELECTED Car's models to the next <select> and I can't do that. I'm pretty novice with all of this stuff. Also I'm using MVC.

From view:

<select name="card_id"> 
<?php foreach ($cars as $car) { 
    if (isset($car->id)) { 
       echo "<option value=\"" . $tcar->id . "\">"; 
       echo $car->car . "</option>\n"; 
    } 
} ?> 
</select> 
<p>Choose model</p> 
<select name="model_id"> 
<?php foreach ($models as $model) { 
    if (isset($model->id)) { 
       echo "<option value=\"" . $model->id . "\">"; 
       echo $model->model . "</option>\n"; 
    } 
} ?> 
</select>

From the model view:

public function getAllCars()
{
    $sql = "SELECT * FROM cars";
    $query = $this->db->prepare($sql);
    $query->execute();
    return $query->fetchAll();
}

I don't know how the model to pick the car model should look like, but I guess it would be something like this:

 public function getmodels()
    {
        $sql = "SELECT * FROM models WHERE
        $query = $this->db->prepare($sql);
        $query->execute();
     return $query->fetchAll();
    }

Also I don't fully understand the part that's inside the select tag so if you could explain it thoroughly to me it would be nice.