DrinkTable class

<?php
namespace DrinkManagement\Model;

use Zend\Db\TableGateway\AbstractTableGateway,
    Zend\Db\Adapter\Adapter,
    Zend\Db\ResultSet\ResultSet,
    Zend\Db\Sql\Select;

class DrinkTable extends AbstractTableGateway
{
    protected $table ='drink';
    protected $tableName ='drink';

    public function __construct(Adapter $adapter)
    {
        $this->adapter = $adapter;
        $this->resultSetPrototype = new ResultSet(new Drink);

        $this->initialize();
    }

    public function fetchAll()
    {
        $resultSet = $this->select();
        return $resultSet;
    }

    public function newSelect() {
        return new Select;
    }

    public function getSelect(&$select,$columnsArray=array())
    {
        $select = new Select;
        return $select->from('drink')->columns($columnsArray);
    }

    public function createIfNotExist($checkColumnsArray,$optionalColumns=array(),&$isRowCreated=null) {
            $rowset=$this->select($checkColumnsArray);
            $row = $rowset->current();
            $id=null;
            if ($row == null) {
                $allColumns=array_merge($checkColumnsArray,$optionalColumns);
                $affectedRows = $this->insert($allColumns);
                if ($affectedRows != 1) {
                    throw new \Exception("error: could not add line to db");
                }
                $id=$this->lastInsertValue;
                $isRowCreated=true;
            } else {
                $id=$row->drink_id;
                $isRowCreated=false;
            }
            return $id;
    }

    //http://stackoverflow.com/questions/6156942/how-do-i-insert-an-empty-row-but-have-the-autonumber-update-correctly

    public function createEmptyRow() {
        $row=array(
        'drink_id' => null
        );
        $affectedRows=$this->insert($row);
        if ($affectedRows != 1) {
            throw new \Exception("error: could not add empty row to db");
        }
        $id=$this->lastInsertValue;
        return $id;
    }

    public function getDrink($id)
    {
        $id  = (int) $id;
        $rowset = $this->select(array('drink_id' => $id));
        $row = $rowset->current();
        if (!$row) {
            throw new \Exception("Could not find row $id");
        }
        return $row;
    }

    public function saveDrink(Drink $drink)
    {
        $data = array(
                        'drink_type_id' => $drink->drink_type_id,
                        'drink_brand_id' => $drink->drink_brand_id,
                        'creation_timestamp' => $drink->creation_timestamp,
                    );

        $id = (int)$drink->id;
        if ($id == 0) {
            $this->insert($data);
        } else {
            if ($this->getDrink($id)) {
                $this->update($data, array('drink_id' => $id));
            } else {
                throw new \Exception('Form id does not exit');
            }
        }
    }

    public function addDrink($drink_type_id, $drink_brand_id = null, $creation_timestamp = null)
    {
        $data = array(            'drink_type_id' => $drink_type_id,
                        'drink_brand_id' => $drink_brand_id,
                        'creation_timestamp' => $creation_timestamp,
                    );
        $affectedRows=$this->insert($data);
                if ($affectedRows != 1) {
            return null;
        }
        return $this->lastInsertValue;
            }

    public function updateDrink($drink_id, $drink_type_id, $drink_brand_id, $creation_timestamp)
    {
        $data = array(
                        'drink_type_id' => $drink->drink_type_id,
                        'drink_brand_id' => $drink->drink_brand_id,
                        'creation_timestamp' => $drink->creation_timestamp,
                            );
        $this->update($data, array(drink_id => $id));
    }

    public function deleteDrink($id)
    {
        $this->delete(array('drink_id' => $id));
    }

}