那么如果第二个块在Codeigniter中嵌套了数据库查询，如何在视图上打印条件特定结果？

Question

So I have this existing snippet on custom php.. I am trying to check whether there are existing painting details in the db.. if painting details r found i need to get details of the latest added ones upto count 6 & print detail accordingly. Here is my code->

<?php
    $pData=mysql_query("select * from painting_data");
    if($pData === FALSE) { 
        echo "<div class='well'>No painting available.</div>";
    }
    else{
        $pDet=mysql_query("Select * from painting_data order by padd desc limit 6");
        while($pD=mysql_fetch_assoc($pDet)){
            $pId=$pD['pid'];
            $pTitle=$pD['ptitle'];
            $pImg=$pD['pimg'];
?>
<div class="col-lg-2 col-md-4 col-sm-6 img-recent-container">
    <img role="button" class="img-thumbnail img-responsive img-recent" onclick="location.href='?p=<?php echo $pId; ?>'" src="..<?php echo $pImg;?>" alt="<?php echo $pTitle;?>"/>
</div>  
<?php   }
    } ?>

Now I am new to CI.. & i am confused on how to separate the data retrieval properly. Since the else block has a query in it as well.. I am confused how not to include it in the view.

Answer 1

You should work with DB data in model only and pass returned results to controller. It is MVC paradigm.

P_m.php (model)

P_m extends CI_Model
{
    public $return = [];

    public function __construct()
    {
        parent::__construct();
        $this->load->database();//or load it in APPPATH . 'config/autoload.php'
    }

    public function p()
    {
        $q = $this->db->query("select * from painting_data");
        $return['error'] = $q->num_rows() > 0 ? FALSE : TRUE;

        $q->free_result();

        if ($return['error'] === FALSE)
        {
            $q = $this->db->query("Select * from painting_data order by padd desc limit 6");
            $this->return = $q->result();
        }

        return $return;
    }
}

P_c.php (controller):

P_c extends CI_Controller
{
    public function __construct()
    {
        parent::__construct();
        $this->load->model('p_m');//if used more often, load it in APPPATH . 'config/config.php'
    }

    public function index()
    {
        $output_data['data_from_p_m'] = $this->p_m->p();
        $this->load->view('p_v', $output_data);
    }
}

p_v.php (view):

if ( $data_from_p_m['error'] === FALSE ) 
{
    var_dump($data_from_p_m);
}
else
{
    echo "<div class='well'>No painting available.</div>";
}

You have to declare array before while loop to be able to get all 6 $pId, $ptitle and $pimg.