Sql.php

<?php

    class Sql extends PDO {
        private $conn;

        public function __construct() {
            $this->conn = new PDO("mysql:host=localhost;dbname=dbphp7", "root", "root");
        }

        private function setParams($statement, $parameters = array()) {
            foreach ($parameters as $key => $value) {
                $statement->setParam($key, $value);
            }
        }

        private function setParam($statement, $key, $value) {
            $statement->bindParam($key, $value);
        }

        public function query($rawQuery, $params = array()) {
            $stmt = $this->conn->prepare($rawQuery);

            $this->setParams($stmt, $params);

            $stmt->execute();

            return $stmt;
        }

        public function select($rawQuery, $params = array()):array {
            $stmt = $this->query($rawQuery, $params);

            return $stmt->fetchAll(PDO::FETCH_ASSOC);
        }
    }

?>