物件導向基礎與物件導向設計入門

example.php

<?php

abstract class Database
{
    public function __construct()
    {
        $this->connect();
    }

    abstract public function connect();

    /**
     * @param $sql
     * @param $values
     * @return mixed
     */
    abstract public function query($sql, $values);

    public function quoteIdentifier($col)
    {
        return $col;
    }

    public function insert($table, array $bind)
    {
        $cols = [];
        $vals = [];
        foreach ($bind as $col => $val) {
            $cols[] = $this->quoteIdentifier($col);
            $vals[] = '?';
        }

        $sql = "INSERT INTO "
            . $this->quoteIdentifier($table)
            . ' (' . implode(', ', $cols) . ') '
            . 'VALUES (' . implode(', ', $vals) . ')';

        return $this->query($sql, $bind);
    }
}

class MysqliDriver extends Database
{
    private $conn = null;

    public function connect()
    {
        $this->conn = new mysqli('localhost', 'root', '123456', 'test');
    }

    public function quoteIdentifier($col)
    {
        return '`' . $col . '`';
    }

    public function query($sql, $values)
    {
        $binds = [];
        $types = str_pad('', count($values), 's');
        $binds[] = &$types;
        foreach ($values as $key => $value) {
            $binds[] = &$values[$key];
        }
        $stmt = $this->conn->prepare($sql);
        call_user_func_array([$stmt, 'bind_param'], $binds);
        $stmt->execute();
        $stmt->close();
    }
}

class Model
{
    /**
     * @var Database
     */
    protected static $db;
    protected $table = 'table';
    protected $data = [];

    public static function setDb(Database $db)
    {
        self::$db = $db;
    }

    public function __construct($data)
    {
        $this->data = $data;
    }

    public function save()
    {
        self::$db->insert($this->table, $this->data);
    }
}

class User extends Model
{
    protected $table = 'users';
}

User::setDb(new MysqliDriver());
$user1 = new User([
    'firstname' => 'John',
    'lastname' => 'Doe',
    'email' => 'john@example.com',
]);
$user1->save();