<?php

class DB{
    public static $host;
    public static $user;
    public static $password;
    public static $database;
    public static $link;

    public static function DBInsert($arg){
        $link = DB::DBlink();
        $res = mysqli_query($link, $arg) or die(mysqli_error($link));
    }

    public static function DBlink(){
        self::$host = "localhost";
        self::$user = "root";
        self::$password = "";
        self::$database = "cdlcrypto";
        self::$link = "";
        $link = mysqli_connect(self::$host, self::$user, self::$password, self::$database);
        if (isset($link) == 0) {
            echo "Unable to connect to MySQL." . PHP_EOL;
            echo "Debugging errno: " . mysqli_connect_errno() . PHP_EOL;
            exit;
        }
        return $link;
    }
    public static function SQLFETCH($sql)
    {
        $link = DB::DBlink();
        $res = mysqli_query($link, $sql) or die(mysqli_error($link));
        $result = [];
        if (isset($res)) {
            while ($item = $res->fetch_object()) {
                $result[] = $item;
            }
            return $result;
        } else {
            return "DB IS EMPTY";
        }
    }
    public function DBclearquery($sql)
    {
        $link = DB::DBlink();
        $res = mysqli_query($link, $sql) or die(mysqli_error($link));
    }
}

var_dump(DB::DBlink());