Clase Abstracta

Database.php

<?php

abstract class Database implements DatabaseCRUD {

}

DatabaseCRUD.php

<?php

interface DatabaseCRUD
{
    public function fetchAll($where = null, $order = null, $limit = null);

    public function find($id);

    public function save(DatabaseModel $model, $params);
}

interface DatabaseModel {
    public function insert($params);

    public function update($id, $params);
}

Main.php

<?php

class Main extends Database
{
    public function saveUser()
    {
        $params = [
            'id' => 1,
            'name' => 'Fred',
            'address' => 'Rocky Hard 112'
        ];

        $this->save(new User(), $params);
    }

    public function saveProduct()
    {
        $params = [
            'id' => 1,
            'brand' => 'Pepsico',
            'name' => 'Lays'
        ];

        $this->save(new Product(), $params);
    }

    public function fetchAll($where = null, $order = null, $limit = null)
    {
        // TODO: Implement fetchAll() method.
    }

    public function find($id)
    {
        // TODO: Implement find() method.
    }

    public function save(DatabaseModel $model, $params)
    {
        // TODO: Implement save() method.
        if ($model->getId()){
            $model->update($model->getId(), $params);
        }else{
            $model->insert($params);
        }
    }
}

Product.php

<?php

class Product implements DatabaseModel
{
    protected $id;

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

    public function setId($id)
    {
        $this->id = $id;
    }

    public function insert($params)
    {
        // TODO: Implement insert() method.
        return $this->getDbTable->insert($params);
    }

    public function update($id, $params)
    {
        // TODO: Implement update() method.
        return $this->getDbTable()->update($id, $params);
    }
}

User.php

<?php

class User implements DatabaseModel
{ 
    protected $id;
    protected $name;
    protected $address;

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

    public function getName()
    {
        return $this->name;
    }

    public function getAddress()
    {
        return $this->address;
    }

    public function setId($id)
    {
        $this->id = $id;
    }

    public function setName($name)
    {
        $this->name = $name;
    }

    public function setAddress($address)
    {
        $this->address = $address;
    }

    public function insert($params)
    {
        // TODO: Implement insert() method.
        return $this->getDbTable->insert($params);
    }

    public function update($id, $params)
    {
        // TODO: Implement update() method.
        return $this->getDbTable()->update($id, $params);
    }
}