proposta.php

<?php

class User implements IEntity
{
    public $id    = null;
    public $name  = '';
    public $email = '';
    public $pass  = '';

    public function hasId()
    {
        return (bool) $this->id;
    }

    public function getRefName()
    {
        return 'users_table';
    }

    public function getData()
    {
        return [
            'id'       => $this->id,
            'name'     => $this->name,
            'email'    => $this->email,
            'password' => $this->pass,
        ];
    }
}

class MysqlRepository extends IRepository
{
    private $conn = null;

    public function __construct(\PDO $connection)
    {
        $this->conn = $connection;
    }

    /**
     * @return bool
     */
    protected function insert(IEnitty $entity)
    {
        $data = $entity->getData();
        unset($data['id']);
        $keys   = array_keys($data);
        $fields = implode('=?,', $keys) . '=?';

        $sql  = "INSERT INTO {$entity->getRefName} {$fields}";
        $stmt = $this->conn->prepare($sql);

        return (bool) $stmt->execute(array_values($data));
    }

    /**
     * @return bool
     */
    protected function update(IEnitty $entity)
    {
        $data = $entity->getData();
        $id = array_shift($data);
        $keys   = array_keys($data);
        $fields = implode('=?,', $keys) . '=?';

        $sql  = "UPDATE {$entity->getRefName} SET {$fields} WHERE id = '{$id}'";
        $stmt = $this->conn->prepare($sql);

        return (bool) $stmt->execute(array_values($data));
    }


    /**
     * @return IEntity
     */
    public function find($refname, $arr = [])
    {
        $where = [];

        foreach ($arr as $key => $value) {
            $where[] = "{$key} = '{$value}'"
        }

        $where = implode(',', $where);

        $sql  = "SELECT * FROM {$refname} WHERE {$where}";
        return $this->conn->query($sql)->fetch(PDO::FETCH_OBJECT);
    }

    /**
     * @return array
     */
    public function findAll($refname, $arr = [])
    {
        $where = [];

        foreach ($arr as $key => $value) {
            $where[] = "{$key} = '{$value}'"
        }

        $where = implode(',', $where);

        $sql  = "SELECT * FROM {$refname} WHERE {$where}";
        return $this->conn->query($sql)->fetchAll(PDO::FETCH_OBJECT);
    }

    /**
     * @return bool
     */
    public function remove(IEnitty $entity);
}


interface IEntity
{
    /**
     * Aqui temos o metodo que retorna se esse o objeto tem
     * id ou não, ou seja, se é um novo objeto ou um que ja existe no banco
     *
     * @return bool
     **/
    public function hasId();
    public function getRefName();
    public function getData();
}

/**
 * aqui temos uma interface de um Repositório
 * o objetivo dela é só padronizar os métodos que serão utilizados para
 * manutenção do objeto que terá que implementar a interface "IEntity"
 **/
abstract IRepository
{
    /**
     * @return bool
     */
    protected function insert(IEnitty $entity);


    /**
     * @return bool
     */
    protected function update(IEnitty $entity);


    /**
     * @return IEntity
     */
    public function find($refname, $arr = []);

    /**
     * @return array
     */
    public function findAll($refname, $arr = []);

    /**
     * @return bool
     */
    public function remove(IEnitty $entity);

    /**
     * @return bool
     */
    public function save(IEnitty $entity)
    {
        if ($entity->hasId()) {
            return $this->insert($entity);
        }

        return $this->update($entity);
    }
}