致命错误：未捕获错误 OOP php 扩展 class

Question

I did mvc app.

There is a class database in file db.php.

<?php
namespace App\DB_con;

class DataBase{

    static $user = "root";
    static $pass = '1234';
    static $host = "localhost";
    static $db   = "mvcApp";

     static function conn_To_DB()
    {

        $user = self::$user;
        $pass = self::$pass;
        $host = self::$host;
        $db   = self::$db;

        $conn = new PDO("mysql:dbname=$db;host=$host", $user, $pass);
        return $conn;

    }
}

I inherit it in another file model_tasks.php.

<?php

namespace app\contol\model;
require_once 'conf/db.php';


use App\DB_con\DataBase as main_model;



class model_tasks extends main_model
{
        public function add_tasks($name, $email){
            $db  = DataBase::conn_To_DB();
            $sql = "INSERT INTO  tasks (name, mail) VALUES ('$name','$email')";
            $result = $db->prepare($sql);
            return $result->execute();

        }
}

Data that get into the method var_dump well. Why the inherited class does not find the class from which it receives the connection to the database error appears? What am I doing wrong?

  Fatal error: Uncaught Error: Class 'app\contol\model\DataBase' not found in /models/model_tasks.php:14 
Stack trace: #0 /controllers/HomeController.php(28): app\contol\model\model_tasks::add_tasks('', '', '') 
#1 /conf/route.php(28): App\Controller\BasicController::add_post() 
#2 /index.php(3): require_once('/....') 
#3 {main} thrown in /models/model_tasks.php on line 14

Answer 1

You use namespace App\DB_con\DataBase via alias main_model , that's why your script doesn't know about original namespace App\DB_con\DataBase , it knows about alias main_model .

But going further as your model_tasks extends your main_model , all parent class methods are available in a child class.

So,

$db = DataBase::conn_To_DB();

can be changed to:

$db = static::conn_To_DB();  // or less secure $db = self::conn_To_DB();